[ { "id": "authors:a79p2-me155", "collection": "authors", "collection_id": "a79p2-me155", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130904-102718969", "type": "article", "title": "Two-photon microscopy of the mouse cochlea in situ for cellular diagnosis", "author": [ { "family_name": "Yang", "given_name": "Xing", "clpid": "Yang-Xing" }, { "family_name": "Pu", "given_name": "Ye", "clpid": "Pu-Ye" }, { "family_name": "Hsieh", "given_name": "Chia-Lung", "clpid": "Hsieh-Chia-Lung" }, { "family_name": "Ong", "given_name": "Cheng Ai", "clpid": "Ong-Cheng-Ai" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Stankovic", "given_name": "Konstantina M.", "clpid": "Stankovic-K-M" } ], "abstract": "Sensorineural hearing loss is the most common type of hearing loss worldwide, yet the underlying cause is typically unknown because the inner ear cannot be biopsied today without destroying hearing, and intracochlear cells have not been imaged with resolution sufficient to establish diagnosis. Intracochlear imaging has been technologically challenging because of the cochlea's small size and encasement in bone. We report, for the first time, imaging of the mouse cochlea in situ without exogenous dyes, through a membranous round window, using a near-infrared femtosecond laser as the excitation and endogenous two-photon excitation fluorescence (TPEF) and second harmonic generation as the contrast mechanisms. We find that TPEF exhibits strong contrast allowing cellular, and even subcellular resolution, and detection of specific, noise-induced pathologic changes. Our results demonstrate that the round window provides a useful access to the cochlea through the middle ear, and they motivate future development of a new and efficient diagnostic tool based on two-photon micro-endoscopy.", "doi": "10.1117/1.JBO.18.3.031104", "issn": "1083-3668", "publisher": "Society of Photo-Optical Instrumentation Engineers", "publication": "Journal of Biomedical Optics", "publication_date": "2013-03", "series_number": "3", "volume": "18", "issue": "3", "pages": "Art. No. 031104" }, { "id": "authors:2kyfx-w7n17", "collection": "authors", "collection_id": "2kyfx-w7n17", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120130-073135307", "type": "article", "title": "Optical diffraction of focused spots and subwavelength structures", "author": [ { "family_name": "Marx", "given_name": "D. S.", "clpid": "Marx-D-S" }, { "family_name": "Psaltis", "given_name": "D.", "clpid": "Psaltis-D" } ], "abstract": "We have developed a numerical diffraction tool for cases in which the incident field is a focused spot and the diffracting structure is a single structure or an aperiodic surface. Our approach uses the integral formulation to solve Maxwell's equations and is different from previously published methods in its choice of basis function. We compared numerical results with experimental measurements of the far-field intensity for a focused spot incident on an aluminum grating, and the comparison was favorable. Finally, we predict the diffraction behavior of the proposed digital video disk format for the next generation of optical disk. Our analysis shows that the reflected signal for this format has a strong dependence on the polarization of the incident light.", "doi": "10.1364/JOSAA.14.001268", "issn": "1084-7529", "publisher": "Optical Society of America", "publication": "Journal of the Optical Society of America A", "publication_date": "2012-01-30", "series_number": "6", "volume": "14", "issue": "6", "pages": "1268-1278" }, { "id": "authors:h5bec-brb96", "collection": "authors", "collection_id": "h5bec-brb96", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120402-094201921", "type": "article", "title": "Three-dimensional scanning microscopy through thin turbid media", "author": [ { "family_name": "Yang", "given_name": "Xing", "clpid": "Yang-Xing" }, { "family_name": "Hsieh", "given_name": "Chia-Lung", "clpid": "Hsieh-Chia-Lung" }, { "family_name": "Pu", "given_name": "Ye", "clpid": "Pu-Ye" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We demonstrate three-dimensional imaging through a thin turbid medium using digital phase conjugation of the second harmonic signal emitted from a beacon nanoparticle. The digitally phase-conjugated focus scans the volume in the vicinity of its initial position through numerically manipulated phase patterns projected onto the spatial light modulator. Accurate three dimensional images of a fluorescent sample placed behind a turbid medium are obtained.", "doi": "10.1364/OE.20.002500", "issn": "1094-4087", "publisher": "Optical Society of America", "publication": "Optics Express", "publication_date": "2012-01-30", "series_number": "3", "volume": "20", "issue": "3", "pages": "2500-2506" }, { "id": "authors:vyd1c-mct77", "collection": "authors", "collection_id": "vyd1c-mct77", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120224-100208813", "type": "article", "title": "Imaging with second-harmonic radiation probes in living tissue", "author": [ { "family_name": "Grange", "given_name": "Rachel", "clpid": "Grange-R" }, { "family_name": "Lanvin", "given_name": "Thomas", "clpid": "Lanvin-T" }, { "family_name": "Hsieh", "given_name": "Chia-Lung", "clpid": "Hsieh-C-L" }, { "family_name": "Pu", "given_name": "Ye", "clpid": "Pu-Y" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We demonstrate that second-harmonic radiation imaging probes are efficient biomarkers for imaging in living tissue. We show that 100 nm and 300 nm BaTiO_3 nanoparticles used as contrast markers could be detected through 50 \u03bcm and 120 \u03bcm of mouse tail tissue in vitro or in vivo. Experimental results and Monte-Carlo simulations are in good agreement.", "doi": "10.1364/BOE.2.002532", "issn": "2156-7085", "publisher": "Optical Society of America", "publication": "Biomedical Optics Express", "publication_date": "2011-09-01", "series_number": "9", "volume": "2", "issue": "9", "pages": "2532-2539" }, { "id": "authors:gyspz-16286", "collection": "authors", "collection_id": "gyspz-16286", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20101210-113403798", "type": "article", "title": "Imaging through turbid layers by scanning the phase conjugated second harmonic radiation from a nanoparticle", "author": [ { "family_name": "Hsieh", "given_name": "Chia-Lung", "clpid": "Hsieh-C-L" }, { "family_name": "Pu", "given_name": "Ye", "clpid": "Pu-Y" }, { "family_name": "Grange", "given_name": "Rachel", "clpid": "Grange-R" }, { "family_name": "Laporte", "given_name": "Gr\u00e9goire", "clpid": "Laporte-G" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We demonstrate imaging through a turbid layer by using digital phase conjugation of the second harmonic field radiated from a beacon nanoparticle. We show that the phase-conjugated focus can be displaced from its initial position by illuminating the same region of the turbid layer with an angular offset. An image is obtained by scanning the phase-conjugated focus through the turbid layer in a region around the nanoparticle. We obtain a clear image of the target by measuring the light transmitted through it when scanning the focused beam.", "doi": "10.1364/OE.18.020723", "issn": "1094-4087", "publisher": "Optical Society of America", "publication": "Optics Express", "publication_date": "2010-09-27", "series_number": "20", "volume": "18", "issue": "20", "pages": "20723-20731" }, { "id": "authors:fqjgf-zez53", "collection": "authors", "collection_id": "fqjgf-zez53", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100630-112422931", "type": "article", "title": "Digital phase conjugation of second harmonic radiation emitted by nanoparticles in turbid media", "author": [ { "family_name": "Hsieh", "given_name": "Chia-Lung", "clpid": "Hsieh-C-L" }, { "family_name": "Pu", "given_name": "Ye", "clpid": "Pu-Y" }, { "family_name": "Grange", "given_name": "Rachel", "clpid": "Grange-R" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We demonstrate focusing coherent light on a nanoparticle through turbid media based on digital optical phase conjugation of second harmonic generation (SHG) field from the nanoparticle. A SHG active nanoparticle inside a turbid medium was excited at the fundamental frequency and emitted SHG field as a point source. The SHG emission was scattered by the turbid medium, and the scattered field was recorded by off-axis digital holography. A phase-conjugated beam was then generated by using a phase-only spatial light modulator and sent back through the turbid medium, which formed a nearly ideal focus on the nanoparticle.", "doi": "10.1364/OE.18.012283", "issn": "1094-4087", "publisher": "Optical Society of America", "publication": "Optics Express", "publication_date": "2010-06-07", "series_number": "12", "volume": "18", "issue": "12", "pages": "12283-12290" }, { "id": "authors:8gkxn-m4536", "collection": "authors", "collection_id": "8gkxn-m4536", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100629-140256405", "type": "article", "title": "Second harmonic generation from nanocrystals under linearly and circularly polarized excitations", "author": [ { "family_name": "Hsieh", "given_name": "Chia-Lung", "clpid": "Hsieh-C-L" }, { "family_name": "Pu", "given_name": "Ye", "clpid": "Pu-Y" }, { "family_name": "Grange", "given_name": "Rachel", "clpid": "Grange-R" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We study second harmonic generation (SHG) from non-centrosymmetric nanocrystals under linearly polarized (LP) and circularly polarized (CP) excitations. Theoretical models are developed for SHG from nanocrystals under both plane-wave and focused excitations. We find that the focused excitation reduces the polarization dependency of the SHG signal. We show that the SHG response under CP excitation is generally inferior to the average of LP excitations over all orientations. We verify the theory by measuring the SHG polar responses from BaTiO_3 nanocrystals with a scanning confocal microscope. The experimental data agrees well with the theory.", "doi": "10.1364/OE.18.011917", "issn": "1094-4087", "publisher": "Optical Society of America", "publication": "Optics Express", "publication_date": "2010-05-24", "series_number": "11", "volume": "18", "issue": "11", "pages": "11917-11932" }, { "id": "authors:hg74m-4gh24", "collection": "authors", "collection_id": "hg74m-4gh24", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100616-110722003", "type": "article", "title": "Nonlinear Optical Properties of Core-Shell Nanocavities for Enhanced Second-Harmonic Generation", "author": [ { "family_name": "Pu", "given_name": "Ye", "clpid": "Pu-Y" }, { "family_name": "Grange", "given_name": "Rachel", "clpid": "Grange-R" }, { "family_name": "Hsieh", "given_name": "Chia-Lung", "clpid": "Hsieh-C-L" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "A nonlinear optical plasmonic core-shell nanocavity is demonstrated as an efficient, subwavelength coherent light source through second-harmonic generation. The nonlinear optical plasmonic nanocavity incorporates a noncentrosymmetric medium, which utilizes the entire mode volume for even-order nonlinear optical processes. In previous plasmonic nanocavities, enhancement of such processes was only possible at the interface but symmetry prohibited in the body. We measured an enhancement of over 500 times in the second-harmonic radiation power. Calculations show that an enhancement of over 3500 times is achievable.", "doi": "10.1103/PhysRevLett.104.207402", "issn": "0031-9007", "publisher": "American Physical Society", "publication": "Physical Review Letters", "publication_date": "2010-05-21", "series_number": "20", "volume": "104", "issue": "20", "pages": "Art. No. 207402" }, { "id": "authors:gdbkz-4qx25", "collection": "authors", "collection_id": "gdbkz-4qx25", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100412-085531492", "type": "article", "title": "Bioconjugation of barium titanate nanocrystals with immunoglobulin G antibody\n for second harmonic radiation imaging probes", "author": [ { "family_name": "Hsieh", "given_name": "Chia-Lung", "clpid": "Hsieh-C-L" }, { "family_name": "Grange", "given_name": "Rachel", "clpid": "Grange-R" }, { "family_name": "Pu", "given_name": "Ye", "clpid": "Pu-Y" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "The second harmonic generation (SHG) active nanocrystals have been demonstrated as attractive imaging probes in nonlinear microscopy due to their coherent, non-bleaching and non-blinking signals with a broad flexibility in the choice of excitation wavelength. For the use of these nanocrystals as biomarkers, it is essential to prepare a chemical interface for specific labeling. We developed a specific labeling scheme for barium titanate (BaTiO_3) nanocrystals which we use as second harmonic radiation imaging probes. The specificity was achieved by covalently coupling antibodies onto the nanocrystals. We demonstrate highly specific labeling of the nanocrystal conjugates in an antibody microarray and also the membrane proteins of live biological cells in vitro. The development of surface functionalization and bioconjugation of SHG active nanocrystals provides the opportunities of applying them to biological studies.", "doi": "10.1016/j.biomaterials.2009.11.096", "issn": "0142-9612", "publisher": "Elsevier", "publication": "Biomaterials", "publication_date": "2010-03", "series_number": "8", "volume": "31", "issue": "8", "pages": "2272-2277" }, { "id": "authors:en0be-tm764", "collection": "authors", "collection_id": "en0be-tm764", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100406-112645598", "type": "article", "title": "3-dimensional electrode patterning within a microfluidic channel using metal ion implantation", "author": [ { "family_name": "Choi", "given_name": "Jae-Woo", "clpid": "Choi-Jae-Woo" }, { "family_name": "Rosset", "given_name": "Samuel", "clpid": "Rosset-Samuel" }, { "family_name": "Niklaus", "given_name": "Muhamed", "clpid": "Niklaus-Muhamed" }, { "family_name": "Adleman", "given_name": "James R.", "clpid": "Adleman-J-R" }, { "family_name": "Shea", "given_name": "Herbert", "clpid": "Shea-Herbert" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "The application of electrical fields within a microfluidic channel enables many forms of manipulation necessary for lab-on-a-chip devices. Patterning electrodes inside the microfluidic channel generally requires multi-step optical lithography. Here, we utilize an ion-implantation process to pattern 3D electrodes within a fluidic channel made of polydimethylsiloxane (PDMS). Electrode structuring within the channel is achieved by ion implantation at a 40\u00b0 angle with a metal shadow mask. The advantages of three-dimensional structuring of electrodes within a fluidic channel over traditional planar electrode designs are discussed. Two possible applications are presented: asymmetric particles can be aligned in any of the three axial dimensions with electro-orientation; colloidal focusing and concentration within a fluidic channel can be achieved through dielectrophoresis. Demonstrations are shown with E. coli, a rod shaped bacteria, and indicate the potential that ion-implanted microfluidic channels have for manipulations in the context of lab-on-a-chip devices.", "doi": "10.1039/b917719a", "issn": "1473-0197", "publisher": "Royal Society of Chemistry", "publication": "Lab on a Chip", "publication_date": "2010", "series_number": "6", "volume": "10", "issue": "6", "pages": "783-788" }, { "id": "authors:cd4sy-m8564", "collection": "authors", "collection_id": "cd4sy-m8564", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100105-112257832", "type": "article", "title": "Heterogenous Catalysis Mediated by Plasmon Heating", "author": [ { "family_name": "Adleman", "given_name": "James R.", "clpid": "Adleman-J-R" }, { "family_name": "Boyd", "given_name": "David A.", "clpid": "Boyd-D-A" }, { "family_name": "Goodwin", "given_name": "David G.", "clpid": "Goodwin-D-G" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We introduce a new method for performing and miniaturizing many types of heterogeneous catalysis involving nanoparticles. The method makes use of the plasmon resonance present in nanoscale metal catalysts to provide the necessary heat of reaction when illuminated with a low-power laser. We demonstrate our approach by reforming a flowing, liquid mixture of ethanol and water over gold nanoparticle catalysts in a microfluidic channel. Plasmon heating of the nanoparticles provides not only the heat of reaction but the means to generate both water and ethanol vapor locally over the catalysts, which in turn allows the chip and the fluid lines to remain at room temperature. The measured products of the reaction, CO_2, CO, and H_2, are consistent with catalytic steam reforming of ethanol. The approach, which we refer to as plasmon-assisted catalysis, is general and can be used with a variety of endothermic catalytic processes involving nanoparticles.", "doi": "10.1021/nl902711n", "issn": "1530-6984", "publisher": "American Chemical Society", "publication": "Nano Letters", "publication_date": "2009-12", "series_number": "12", "volume": "9", "issue": "12", "pages": "4417-4423" }, { "id": "authors:cpfkq-aje87", "collection": "authors", "collection_id": "cpfkq-aje87", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20091210-092703084", "type": "article", "title": "Electroactive micro and nanowells for optofluidic storage", "author": [ { "family_name": "Cordovez", "given_name": "Bernardo", "clpid": "Cordovez-B" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Erickson", "given_name": "David", "clpid": "Erickson-D" } ], "abstract": "This paper reports an optofluidic architecture which enables reversible trapping, detection and long term storage of spectrally multiplexed semiconductor quantum dot cocktails in electrokinetically active wells ranging in size from 200nm to 5\u03bcm. Here we describe the microfluidic delivery of these cocktails, fabrication method and principal of operation for the wells, and characterize the readout capabilities, storage and erasure speeds, internal spatial signal uniformity and potential storage density of the devices. We report storage and erase speeds of less than 153ms and 30ms respectively and the ability to provide 6-bit storage in a single 200nm well through spectral and intensity multiplexing. Furthermore, we present a novel method for enabling passive long term storage of the quantum dots in the wells by transporting them through an agarose gel matrix. We envision that this technique could find eventual application in fluidic memory or display devices.", "doi": "10.1364/OE.17.021134", "issn": "1094-4087", "publisher": "Optical Society of America", "publication": "Optics Express", "publication_date": "2009-11-09", "series_number": "23", "volume": "17", "issue": "23", "pages": "21134-21148" }, { "id": "authors:58ar3-35k81", "collection": "authors", "collection_id": "58ar3-35k81", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090928-140823265", "type": "article", "title": "A multi-color fast-switching microfluidic droplet dye laser", "author": [ { "family_name": "Tang", "given_name": "Sindy K. Y.", "clpid": "Tang-Sindy-K-Y" }, { "family_name": "Li", "given_name": "Zhenyu", "clpid": "Li-Zhenyu" }, { "family_name": "Abate", "given_name": "Adam R.", "orcid": "0000-0001-9614-4831", "clpid": "Abate-Adam-R" }, { "family_name": "Agresti", "given_name": "Jeremy J.", "clpid": "Agresti-J-J" }, { "family_name": "Weitz", "given_name": "David A.", "clpid": "Weitz-D-A" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Whitesides", "given_name": "George M.", "orcid": "0000-0001-9451-2442", "clpid": "Whitesides-G-M" } ], "abstract": "We describe a multi-color microfluidic dye laser operating in whispering gallery mode based on a train of alternating droplets containing solutions of different dyes; this laser is capable of switching the wavelength of its emission between 580 nm and 680 nm at frequencies up to 3.6 kHz -\u2014 the fastest among all dye lasers reported; it has potential applications in on-chip spectroscopy and flow cytometry.", "doi": "10.1039/b914066b", "issn": "1473-0197", "publisher": "Royal Society of Chemistry", "publication": "Lab on a Chip", "publication_date": "2009-10-07", "series_number": "19", "volume": "9", "issue": "19", "pages": "2767-2771" }, { "id": "authors:jnh54-m9654", "collection": "authors", "collection_id": "jnh54-m9654", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20091030-080315884", "type": "article", "title": "Lithium niobate nanowires synthesis, optical properties, and manipulation", "author": [ { "family_name": "Grange", "given_name": "Rachel", "clpid": "Grange-Rachel" }, { "family_name": "Choi", "given_name": "Jae-Woo", "clpid": "Choi-Jae-Woo" }, { "family_name": "Hsieh", "given_name": "Chia-Lung", "clpid": "Hsieh-Chia-Lung" }, { "family_name": "Pu", "given_name": "Ye", "clpid": "Pu-Ye" }, { "family_name": "Magrez", "given_name": "Arnaud", "clpid": "Magrez-A" }, { "family_name": "Smajda", "given_name": "Rita", "clpid": "Smajda-Rita" }, { "family_name": "Forr\u00f3", "given_name": "L\u00e1szl\u00f3", "clpid": "Forr\u00f3-L\u00e1szl\u00f3" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "Free-standing lithium niobate nanowires (LiNbO_3) are synthesized by the hydrothermal route. The polarization response of the second harmonic generation (SHG) signal is measured in a single nanowire and used to identify the crystal orientation by matching with bulk LiNbO_3 nonlinear optical susceptibility. The electrical manipulation of a LiNbO_3 nanowire and its monitoring through the SHG signal in a fluidic setup are demonstrated.", "doi": "10.1063/1.3236777", "issn": "0003-6951", "publisher": "American Institute of Physics", "publication": "Applied Physics Letters", "publication_date": "2009-10-05", "series_number": "14", "volume": "95", "issue": "14", "pages": "Art. No. 143105" }, { "id": "authors:sz0ys-zap85", "collection": "authors", "collection_id": "sz0ys-zap85", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090603-080059405", "type": "article", "title": "Optofluidic evanescent dye laser based on a distributed feedback circular grating", "author": [ { "family_name": "Song", "given_name": "Wuzhou", "clpid": "Song-Wuzhou" }, { "family_name": "Vasdekis", "given_name": "Andreas E.", "clpid": "Vasdekis-A-E" }, { "family_name": "Li", "given_name": "Zhenyu", "clpid": "Li-Zhenyu" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We demonstrate an optofluidic evanescent laser based on a solid circular distributed feedback grating with the dye solution acting as the cladding layer. The laser mode is confined within the grating and experiences optical gain via the interaction between its evanescent component with the dye solution. Above a pump energy of 9.5 \u00b5J/pulse, the laser exhibited single mode operation at 571 nm. Stable, narrow-linewidth emission was observed for a wide range of fluid refractive indices, even for those lower than of polydimethylsiloxane. We attribute this property to the evanescent coupling of the laser mode with the fluidic gain", "doi": "10.1063/1.3124652", "issn": "0003-6951", "publisher": "American Institute of Physics", "publication": "Applied Physics Letters", "publication_date": "2009-04-20", "series_number": "16", "volume": "94", "issue": "16", "pages": "Art. No. 161110" }, { "id": "authors:6jqnk-1gr52", "collection": "authors", "collection_id": "6jqnk-1gr52", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090415-090653684", "type": "article", "title": "Three-dimensional harmonic holographic microcopy using nanoparticles as probes for cell imaging", "author": [ { "family_name": "Hsieh", "given_name": "Chia-Lung", "clpid": "Hsieh-C-L" }, { "family_name": "Grange", "given_name": "Rachel", "clpid": "Grange-R" }, { "family_name": "Pu", "given_name": "Ye", "clpid": "Pu-Y" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "Luminescent markers play a key role in imaging techniques for life science since they provide a contrast mechanism between signal and background. We describe a new type of marker using second harmonic generation (SHG) from noncentrosymmetric BaTiO_3 nanocrystals. These nanoparticles are attractive due to their stable, non-saturating and coherent signal with a femtosecond-scale response time and broad flexibility in the choice of excitation wavelength. We obtained monodispersed BaTiO_3 nanoparticles in colloidal suspensions by coating the particle surface with amine groups. We characterized the SHG efficiency of 90-nm BaTiO_3 particles experimentally and theoretically. Moreover, we use the coherent SHG signal from BaTiO_3 nanoparticles for three-dimensional (3D) imaging without scanning. We built a harmonic holographic (H^2) microscope which records digital holograms at the second harmonic frequency. For the first time, high-resolution 3D distributions of these SHG markers in mammalian cells are successfully captured and interpreted by the H^2 microscope.", "issn": "1094-4087", "publisher": "Optical Society of America", "publication": "Optics Express", "publication_date": "2009-02-16", "series_number": "4", "volume": "17", "issue": "4", "pages": "2880-2891" }, { "id": "authors:k8kzj-a5495", "collection": "authors", "collection_id": "k8kzj-a5495", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:SONapl09", "type": "article", "title": "Low-order distributed feedback optofluidic dye laser with reduced threshold", "author": [ { "family_name": "Song", "given_name": "Wuzhou", "clpid": "Song-Wuzhou" }, { "family_name": "Vasdekis", "given_name": "Andreas E.", "clpid": "Vasdekis-A-E" }, { "family_name": "Li", "given_name": "Zhenyu", "clpid": "Li-Zhenyu" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We report the demonstration of low order distributed feedback (DFB) optofluidic dye lasers with reduced threshold. The laser chips were realized in polydimethylsiloxane using replica molding with two masters. A comparison between first, second, and third order DFB dye lasers was performed, while the second order DFB dye laser exhibited the lowest pump threshold of 78 nJ/pulse. Compared to previous reports on higher order Bragg grating structures, the pump threshold in this work is approximately 30-fold lower than the state of the art due to the reduction in the cavity losses and the more efficient pumping configuration.", "doi": "10.1063/1.3079799", "issn": "0003-6951", "publisher": "American Institute of Physics", "publication": "Applied Physics Letters", "publication_date": "2009-02-02", "series_number": "5", "volume": "94", "issue": "5", "pages": "Art No. 0511117" }, { "id": "authors:f640y-5p079", "collection": "authors", "collection_id": "f640y-5p079", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CUIpnas08", "type": "article", "title": "Lensless high-resolution on-chip optofluidic microscopes for Caenorhabditis elegans and cell imaging", "author": [ { "family_name": "Cui", "given_name": "Xiquan", "clpid": "Cui-Xiquan" }, { "family_name": "Lee", "given_name": "Lap Man", "clpid": "Lee-Lap-Man" }, { "family_name": "Heng", "given_name": "Xin", "clpid": "Heng-Xin" }, { "family_name": "Zhong", "given_name": "Weiwei", "clpid": "Zhong-Weiwei" }, { "family_name": "Sternberg", "given_name": "Paul W.", "orcid": "0000-0002-7699-0173", "clpid": "Sternberg-P-W" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Yang", "given_name": "Changhuei", "orcid": "0000-0001-8791-0354", "clpid": "Yang-Changhuei" } ], "abstract": "Low-cost and high-resolution on-chip microscopes are vital for reducing cost and improving efficiency for modern biomedicine and bioscience. Despite the needs, the conventional microscope design has proven difficult to miniaturize. Here, we report the implementation and application of two high-resolution (\u22480.9 \u03bcm for the first and \u22480.8 \u03bcm for the second), lensless, and fully on-chip microscopes based on the optofluidic microscopy (OFM) method. These systems abandon the conventional microscope design, which requires expensive lenses and large space to magnify images, and instead utilizes microfluidic flow to deliver specimens across array(s) of micrometer-size apertures defined on a metal-coated CMOS sensor to generate direct projection images. The first system utilizes a gravity-driven microfluidic flow for sample scanning and is suited for imaging elongate objects, such as Caenorhabditis elegans; and the second system employs an electrokinetic drive for flow control and is suited for imaging cells and other spherical/ellipsoidal objects. As a demonstration of the OFM for bioscience research, we show that the prototypes can be used to perform automated phenotype characterization of different Caenorhabditis elegans mutant strains, and to image spores and single cellular entities. The optofluidic microscope design, readily fabricable with existing semiconductor and microfluidic technologies, offers low-cost and highly compact imaging solutions. More functionalities, such as on-chip phase and fluorescence imaging, can also be readily adapted into OFM systems. We anticipate that the OFM can significantly address a range of biomedical and bioscience needs, and engender new microscope applications.", "doi": "10.1073/pnas.0804612105", "pmcid": "PMC2488383", "issn": "0027-8424", "publisher": "National Academy of Sciences", "publication": "Proceedings of the National Academy of Sciences of the United States of America", "publication_date": "2008-08-05", "series_number": "31", "volume": "105", "issue": "31", "pages": "10670-10675" }, { "id": "authors:ngqz1-whq73", "collection": "authors", "collection_id": "ngqz1-whq73", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160801-141142224", "type": "article", "title": "Chemical Separations by Bubble-Assisted Interphase Mass-Transfer", "author": [ { "family_name": "Boyd", "given_name": "David A.", "clpid": "Boyd-D-A" }, { "family_name": "Adleman", "given_name": "James R.", "clpid": "Adleman-J-R" }, { "family_name": "Goodwin", "given_name": "David G.", "clpid": "Goodwin-D-G" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We show that when a small amount of heat is added close to a liquid\u2212vapor interface of a captive gas bubble in a microchannel, interphase mass-transfer through the bubble can occur in a controlled manner with only a slight change in the temperature of the fluid. We demonstrate that this method, which we refer to as bubble-assisted interphase mass-transfer (BAIM), can be applied to interphase chemical separations, e.g., simple distillation, without the need for high temperatures, vacuum, or active cooling. Although any source of localized heating could be used, we illustrate BAIM with an all-optical technique that makes use of the plasmon resonance in an array of nanoscale metal structures that are incorporated into the channel to produce localized heating of the fluid when illuminated by a stationary low-power laser.", "doi": "10.1021/ac702174t", "issn": "0003-2700", "publisher": "American Chemical Society", "publication": "Analytical Chemistry", "publication_date": "2008-04-01", "series_number": "7", "volume": "80", "issue": "7", "pages": "2452-2456" }, { "id": "authors:qybsa-23050", "collection": "authors", "collection_id": "qybsa-23050", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:PUYao08", "type": "article", "title": "Harmonic holography: a new holographic principle", "author": [ { "family_name": "Pu", "given_name": "Ye", "clpid": "Pu-Y" }, { "family_name": "Centurion", "given_name": "Martin", "clpid": "Centurion-M" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "The process of second harmonic generation (SHG) has a unique property of forming a sharp optical contrast between noncentrosymmetric crystalline materials and other types of material, which is a highly valuable asset for contrast microscopy. The coherent signal obtained through SHG also allows for the recording of holograms at high spatial and temporal resolution, enabling whole-field four-dimensional microscopy for highly dynamic microsystems and nanosystems. Here we describe a new holographic principle, harmonic holography (H2), which records holograms between independently generated second harmonic signals and reference. We experimentally demonstrate this technique with digital holographic recording of second harmonic signals upconverted from an ensemble of second harmonic generating nanocrystal clusters under femtosecond laser excitation. Our results show that harmonic holography is uniquely suited for ultrafast four-dimensional contrast microscopy.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "2008-02-01", "series_number": "4", "volume": "47", "issue": "4", "pages": "A103-A110" }, { "id": "authors:5zdtv-r8396", "collection": "authors", "collection_id": "5zdtv-r8396", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161128-131905468", "type": "article", "title": "Optical phase conjugation for turbidity suppression in biological samples", "author": [ { "family_name": "Yaqoob", "given_name": "Zahid", "clpid": "Yaqoob-Z" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Feld", "given_name": "Michael S.", "clpid": "Feld-M-S" }, { "family_name": "Yang", "given_name": "Changhuei", "orcid": "0000-0001-8791-0354", "clpid": "Yang-Changhuei" } ], "abstract": "Elastic optical scattering, the dominant light-interaction process in biological tissues, prevents tissues from being transparent. Although scattering may appear stochastic, it is in fact deterministic in nature. We show that, despite experimental imperfections, optical phase conjugation (\u03bb = 532 nm) can force a transmitted light field to retrace its trajectory through a biological target and recover the original light field. For a 0.69-mm-thick chicken breast tissue section, we can enhance point-source light return by a factor of ~5 x 10^3 and achieve a light transmission enhancement factor of 3.8 within a collection angle of 29\u00b0. Additionally, we find that the reconstruction's quality, measured by the width of the reconstructed point source, is independent of tissue thickness (up to a thickness of 0.69 mm). This phenomenon may be used to enhance light transmission through tissue, enable measurement of small tissue movements, and form the basis of new tissue imaging techniques.", "doi": "10.1038/nphoton.2007.297", "pmcid": "PMC2688902", "issn": "1749-4885", "publisher": "Nature Publishing Group", "publication": "Nature Photonics", "publication_date": "2008-02", "series_number": "2", "volume": "2", "issue": "2", "pages": "110-115" }, { "id": "authors:e57nk-vba48", "collection": "authors", "collection_id": "e57nk-vba48", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:TSAprb08", "type": "article", "title": "Magnifying perfect lens and superlens design by coordinate transformation", "author": [ { "family_name": "Tsang", "given_name": "Mankei", "clpid": "Tsang-M" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "The coordinate transformation technique is applied to the design of perfect lenses and superlenses. In particular, anisotropic metamaterials that magnify two-dimensional planar images beyond the diffraction limit are designed by the use of oblate spheroidal coordinates. The oblate spheroidal perfect lens or superlens can naturally be used in reverse for lithography of planar subwavelength patterns.", "doi": "10.1103/PhysRevB.77.035122", "issn": "1098-0121", "publisher": "Physical Review B", "publication": "Physical Review B", "publication_date": "2008-01-15", "series_number": "3", "volume": "77", "issue": "3", "pages": "Art. No. 035122" }, { "id": "authors:t1t9x-jjj47", "collection": "authors", "collection_id": "t1t9x-jjj47", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HENoe07", "type": "article", "title": "An optical tweezer actuated, nanoaperture-grid based optofluidic microscope implementation method", "author": [ { "family_name": "Heng", "given_name": "Xin", "clpid": "Heng-Xin" }, { "family_name": "Hsiao", "given_name": "Edward", "clpid": "Hsiao-Edward" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Yang", "given_name": "Changhuei", "orcid": "0000-0001-8791-0354", "clpid": "Yang-Changhuei" } ], "abstract": "We report a novel grid based Optofluidic Microscope (OFM) method where a closely spaced 2D grid of nanoapertures (diameter = 100 nm, separation = 2.5 \u03bcm) provided patterned illumination. We achieved a one-to-one mapping of the light transmissions through the nanoapertures onto a high-speed CCD camera. By optically tweezing a targeted sample across the grid in a controlled fashion and recording the time varying light reception from the nanoapertures, we were able to generate high-resolution images of the sample. The achievable resolution limit of the prototype was ~ 110 nm (Sparrow's criterion) under optimal conditions. We demonstrated the technique by imaging polystyrene beads and pollen spores.", "doi": "10.1364/OE.15.016367", "issn": "1094-4087", "publisher": "Optical Society of America", "publication": "Optics Express", "publication_date": "2007-12-10", "series_number": "25", "volume": "15", "issue": "25", "pages": "16367-16375" }, { "id": "authors:4b07t-ydy41", "collection": "authors", "collection_id": "4b07t-ydy41", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:PUYapl07", "type": "article", "title": "Optical parametric generation in periodically poled KTiOPO4 via extended phase matching", "author": [ { "family_name": "Pu", "given_name": "Ye", "clpid": "Pu-Ye" }, { "family_name": "Wu", "given_name": "Jie", "clpid": "Wu-Jie" }, { "family_name": "Tsang", "given_name": "Mankei", "clpid": "Tsang-Mankei" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We report an experimental demonstration of optical parametric generation in a periodically poled KTiOPO4 crystal based on the principle of mirrorless optical parametric oscillation. A femtosecond pump pulse spectrally centered at 792 nm from a Ti:sapphire amplifier is prechirped to minimize Kerr effects. The pump pulse is then injected into the nonlinear crystal and down converted to signal and idler pulses, approximately centered at 1584 nm, via amplified spontaneous parametric down conversion in a copropagating type-II quasiphase matching configuration. The maximum internal downconversion efficiency is 43%, the highest ever reported for optical parametric generators based on KTiOPO4 crystals. Such a device may find applications in optical signal processing and biological imaging.", "doi": "10.1063/1.2790825", "issn": "0003-6951", "publisher": "Applied Physics Letters", "publication": "Applied Physics Letters", "publication_date": "2007-09-24", "series_number": "13", "volume": "91", "issue": "13", "pages": "Art. No. 131120" }, { "id": "authors:vmfee-kgb97", "collection": "authors", "collection_id": "vmfee-kgb97", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:TSAoe07", "type": "article", "title": "Theory of resonantly enhanced near-field imaging", "author": [ { "family_name": "Tsang", "given_name": "Mankei", "clpid": "Tsang-M" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We investigate the fundamental issues of power transfer and far-field retrieval of subwavelength information in resonantly enhanced near-field imaging systems. It is found that high-quality resonance of the imaging system, such as that provided by dielectric resonators, can drastically enhance the power transfer from the object to the detector or the working distance. The optimal power transfer condition is shown to be the same as the critical coupling condition for resonators. The combination of a dielectric planar resonator with a solid immersion lens is proposed to project resonantly enhanced near-field spatial frequency components into the far field with the same resolution limit as that for solid immersion microscopy, but with much improved signal power throughput or working distance for resonant spatial frequencies.", "issn": "1094-4087", "publisher": "Optical Society of America", "publication": "Optics Express", "publication_date": "2007-09-17", "series_number": "19", "volume": "15", "issue": "19", "pages": "11959-11970" }, { "id": "authors:j0c73-axg34", "collection": "authors", "collection_id": "j0c73-axg34", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CHEapl07", "type": "article", "title": "Nanoimprinted circular grating distributed feedback dye laser", "author": [ { "family_name": "Chen", "given_name": "Yan", "clpid": "Chen-Yan" }, { "family_name": "Li", "given_name": "Zhenyu", "clpid": "Li-Zhenyu" }, { "family_name": "Zhang", "given_name": "Zhaoyu", "clpid": "Zhang-Zhaoyu" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Scherer", "given_name": "Axel", "orcid": "0000-0002-2160-9064", "clpid": "Scherer-A" } ], "abstract": "The authors demonstrate an optically pumped surface emitting polymer dye laser fabricated by nanoimprint lithography. The laser is based on an organic dye hosted within a poly(methylmethacrylate) matrix coated on a transparent substrate, and the laser cavity consists of a second order circular grating distributed feedback structure. The authors achieved lasing at 618 nm with 0.18 nm linewidth and 1.31 \u00b5J/mm^2 pump threshold. The nanoimprinted solid-state dye laser offers a low-cost coherent light source for laboratory-on-chip spectroscopy systems. The laser also has a low pump threshold and a geometry well matched to light-emitting diode pump sources, which provide an interesting alternative for constructing portable polymer laser devices.", "doi": "10.1063/1.2757600", "issn": "0003-6951", "publisher": "Applied Physics Letters", "publication": "Applied Physics Letters", "publication_date": "2007-07-30", "series_number": "5", "volume": "91", "issue": "5", "pages": "Art. No. 051109" }, { "id": "authors:xkecc-4zv59", "collection": "authors", "collection_id": "xkecc-4zv59", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:EGGapl07", "type": "article", "title": "Trapping of dielectric particles with light-induced space-charge fields", "author": [ { "family_name": "Eggert", "given_name": "H. A.", "clpid": "Eggert-H-A" }, { "family_name": "Kuhnert", "given_name": "F. Y.", "clpid": "Kuhnert-F-Y" }, { "family_name": "Buse", "given_name": "K.", "clpid": "Buse-K" }, { "family_name": "Adleman", "given_name": "J. R.", "clpid": "Adleman-J-R" }, { "family_name": "Psaltis", "given_name": "D.", "clpid": "Psaltis-D" } ], "abstract": "Light-induced space-charge fields in lithium niobate crystals are used to trap and manipulate dielectric particles on the surface of such crystals. Without any external voltage source, strong field gradients are present in the proximity of the crystal surface. These are used to trap particles with diameters in the range between 100 nm and some tens of micrometers.", "doi": "10.1063/1.2748089", "issn": "0003-6951", "publisher": "Applied Physics Letters", "publication": "Applied Physics Letters", "publication_date": "2007-06-11", "series_number": "24", "volume": "90", "issue": "24", "pages": "Art. No. 241909" }, { "id": "authors:7xm4w-wqt53", "collection": "authors", "collection_id": "7xm4w-wqt53", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CENpra07", "type": "article", "title": "Modulational instability in nonlinearity-managed optical media", "author": [ { "family_name": "Centurion", "given_name": "Martin", "clpid": "Centurion-M" }, { "family_name": "Porter", "given_name": "Mason A.", "clpid": "Porter-M-A" }, { "family_name": "Pu", "given_name": "Ye", "clpid": "Pu-Y" }, { "family_name": "Kevrekidis", "given_name": "P. G.", "orcid": "0000-0002-7714-3689", "clpid": "Kevrekidis-P-G" }, { "family_name": "Frantzeskakis", "given_name": "D. J.", "clpid": "Frantzeskakis-D-J" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We investigate analytically, numerically, and experimentally the modulational instability in a layered, cubically nonlinear (Kerr) optical medium that consists of alternating layers of glass and air. We model this setting using a nonlinear Schr\u00f6dinger (NLS) equation with a piecewise constant nonlinearity coefficient and conduct a theoretical analysis of its linear stability, obtaining a Kronig-Penney equation whose forbidden bands correspond to the modulationally unstable regimes. We find very good quantitative agreement between the theoretical analysis of the Kronig-Penney equation, numerical simulations of the NLS equation, and the experimental results for the modulational instability. Because of the periodicity in the evolution variable arising from the layered medium, we find multiple instability regions rather than just the one that would occur in uniform media.", "doi": "10.1103/PhysRevA.75.063804", "issn": "1050-2947", "publisher": "Physical Review A", "publication": "Physical Review A", "publication_date": "2007-06-01", "series_number": "6", "volume": "75", "issue": "6", "pages": "Art. No. 063804" }, { "id": "authors:gdq6v-8dc90", "collection": "authors", "collection_id": "gdq6v-8dc90", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LIZieeejstqe07", "type": "article", "title": "Optofluidic Distributed Feedback Dye Lasers", "author": [ { "family_name": "Li", "given_name": "Zhenyu", "clpid": "Li-Zhenyu" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We review our recent work on poly(dimethylsiloxane) (PDMS)-based optofluidic dye lasers using a guided wave distributed feedback (DFB) cavity. We show experimental results of single-mode operation, an integrated laser array, multiple color dye lasing, mechanical and fluidic tuning, and monolithic integration with microfluidic circuits. Potential applications and future directions are discussed.", "doi": "10.1109/JSTQE.2007.894051", "issn": "1077-260X", "publisher": "IEEE", "publication": "IEEE Journal of Selected Topics in Quantum Electronics", "publication_date": "2007-03", "series_number": "2", "volume": "13", "issue": "2", "pages": "185-193" }, { "id": "authors:rk09a-k5q28", "collection": "authors", "collection_id": "rk09a-k5q28", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CORapl07", "type": "article", "title": "Trapping and storage of particles in electroactive microwells", "author": [ { "family_name": "Cordovez", "given_name": "Bernardo", "clpid": "Cordovez-B" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Erickson", "given_name": "David", "clpid": "Erickson-D" } ], "abstract": "The authors describe electroactive microwells which exploit highly localized electrokinetic effects in order to actively concentrate, confine, store, and reject particles in well defined geometries. In this letter the authors present experimental results demonstrating repeatable trapping and repulsion of polystyrene particles in wells ranging in diameter from 6 to 20 \u00b5m in the presence of a superimposed pressure driven flow. A comprehensive finite element model is developed to describe the transport physics involved in the attraction and repulsion processes. Immediate applications include active cell trapping, particle concentration and unlabeled sensing.", "doi": "10.1063/1.2430775", "issn": "0003-6951", "publisher": "Applied Physics Letters", "publication": "Applied Physics Letters", "publication_date": "2007-01-08", "series_number": "2", "volume": "90", "issue": "2", "pages": "Art. No. 024102" }, { "id": "authors:t5ft7-pbk52", "collection": "authors", "collection_id": "t5ft7-pbk52", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CENprl06b", "type": "article", "title": "Modulational Instability in a Layered Kerr Medium: Theory and Experiment", "author": [ { "family_name": "Centurion", "given_name": "Martin", "clpid": "Centurion-M" }, { "family_name": "Porter", "given_name": "Mason A.", "clpid": "Porter-M-A" }, { "family_name": "Pu", "given_name": "Ye", "clpid": "Pu-Y" }, { "family_name": "Kevrekidis", "given_name": "P. G.", "orcid": "0000-0002-7714-3689", "clpid": "Kevrekidis-P-G" }, { "family_name": "Frantzeskakis", "given_name": "D. J.", "clpid": "Frantzeskakis-D-J" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We present the first experimental investigation of modulational instability in a layered Kerr medium. The particularly interesting and appealing feature of our configuration, consisting of alternating glass-air layers, is the piecewise-constant nature of the material properties, which allows a theoretical linear stability analysis leading to a Kronig-Penney equation whose forbidden bands correspond to the modulationally unstable regimes. We find very good quantitative agreement between theoretical, numerical, and experimental diagnostics of the modulational instability. Because of the periodicity in the evolution variable arising from the layered medium, there are multiple instability regions rather than just one as in a uniform medium.", "doi": "10.1103/PhysRevLett.97.234101", "issn": "0031-9007", "publisher": "American Physical Society", "publication": "Physical Review Letters", "publication_date": "2006-12-08", "series_number": "23", "volume": "97", "issue": "23", "pages": "Art. No. 234101" }, { "id": "authors:ycfzc-7vn74", "collection": "authors", "collection_id": "ycfzc-7vn74", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CUIol06", "type": "article", "title": "Slanted hole array beam profiler (SHArP)\u2014a high-resolution portable beam profiler based on a linear aperture array", "author": [ { "family_name": "Cui", "given_name": "Xiquan", "clpid": "Cui-Xiquan" }, { "family_name": "Heng", "given_name": "Xin", "clpid": "Heng-Xin" }, { "family_name": "Wu", "given_name": "Jigang", "clpid": "Wu-Jigang" }, { "family_name": "Yaqoob", "given_name": "Zahid", "clpid": "Yaqoob-Z" }, { "family_name": "Scherer", "given_name": "Axel", "orcid": "0000-0002-2160-9064", "clpid": "Scherer-A" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Yang", "given_name": "Changhuei", "orcid": "0000-0001-8791-0354", "clpid": "Yang-Changhuei" } ], "abstract": "We demonstrate a novel high-resolution portable beam profiler based on a slanted linear array of small apertures, termed a slanted hole array beam profiler (SHArP). The apertures are directly fabricated on a metal-coated CMOS imaging sensor. With a single linear scan, the aperture array can establish a virtual grid of sampling points for beam profiling. With our prototype, we demonstrate beam profiling of Gaussian beams over an area of 66.5 \u03bcm\u00d766.5 \u03bcm with a resolution of 0.8 \u03bcm (compare with the CMOS pixel size of 10 \u03bcm). The resolution can be improved into the range of submicrometers by fabricating smaller apertures. The good correspondence between the measured and calculated beam profiles proves the fidelity of our new beam profiling scheme.", "issn": "0146-9592", "publisher": "Optical Society of America", "publication": "Optics Letters", "publication_date": "2006-11-01", "series_number": "21", "volume": "31", "issue": "21", "pages": "3161-3163" }, { "id": "authors:bxxwe-hre94", "collection": "authors", "collection_id": "bxxwe-hre94", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LIZoe06b", "type": "article", "title": "Mechanically tunable optofluidic distributed feedback dye laser", "author": [ { "family_name": "Li", "given_name": "Zhenyu", "clpid": "Li-Zhenyu" }, { "family_name": "Zhang", "given_name": "Zhaoyu", "clpid": "Zhang-Zhaoyu" }, { "family_name": "Scherer", "given_name": "Axel", "orcid": "0000-0002-2160-9064", "clpid": "Scherer-A" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "A continuously tunable optofluidic distributed feedback (DFB) dye laser was demonstrated on a monolithic replica molded poly(dimethylsiloxane) (PDMS) chip. The optical feedback was provided by a phase-shifted higher order Bragg grating embedded in the liquid core of a single mode buried channel waveguide. Due to the soft elastomeric nature of PDMS, the laser frequency could be tuned by mechanically stretching the grating period. In principle, the mechanical tuning range is only limited by the gain bandwidth. A tuning range of nearly 60nm was demonstrated from a single dye laser chip by combining two common dye molecules Rhodamine 6G and Rhodamine 101. Single-mode operation was maintained with less than 0.1nm linewidth. Because of the higher order grating, a single laser, when operated with different dye solutions, can provide tunable light output covering the entire spectrum from near UV to near IR in which efficient laser dyes are available. An array of five DFB dye lasers with different grating periods was also demonstrated on a chip. Such tunable integrated laser arrays are expected to become key components in inexpensive advanced spectroscopy chips.", "issn": "1094-4087", "publisher": "Optical Society of America", "publication": "Optics Express", "publication_date": "2006-10-30", "series_number": "22", "volume": "14", "issue": "22", "pages": "10494-10499" }, { "id": "authors:9q5h1-tg975", "collection": "authors", "collection_id": "9q5h1-tg975", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HENoe06", "type": "article", "title": "Characterization of light collection through a subwavelength aperture from a point source", "author": [ { "family_name": "Heng", "given_name": "Xin", "clpid": "Heng-Xin" }, { "family_name": "Cui", "given_name": "Xiquan", "clpid": "Cui-Xiquan" }, { "family_name": "Knapp", "given_name": "David W.", "clpid": "Knapp-D-W" }, { "family_name": "Wu", "given_name": "Jigang", "clpid": "Wu-Jigang" }, { "family_name": "Yaqoob", "given_name": "Zahid", "clpid": "Yaqoob-Z" }, { "family_name": "McDowell", "given_name": "Emily J.", "clpid": "McDowell-E-J" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Yang", "given_name": "Changhuei", "orcid": "0000-0001-8791-0354", "clpid": "Yang-Changhuei" } ], "abstract": "We experimentally measure and theoretically model the light transmission characteristics of subwavelength apertures. The characterization consists of translating a point source at varying vertical height and lateral displacement from the aperture and measuring the resulting transmission. We define the variation of the transmission with lateral source displacement as the collection mode point spread function (CPSF). This transmission geometry is particularly relevant to subwavelength aperture based imaging devices and enables determination of their resolution. This study shows that the achieved resolutions degrade as a function of sample height and that the behavior of sensor devices based on the use of apertures for detection is different from those devices where the apertures are used as light sources. In addition, we find that the measured CPSF is dependent on the collection numerical aperture (NA). Finally, we establish that resolution beyond the diffraction limit for a nominal optical wavelength of 650 nm and nominal medium refractive index of 1.5 is achievable with subwavelength aperture based devices when the aperture size is smaller than 225 nm.", "issn": "1094-4087", "publisher": "Optical Society of America", "publication": "Optics Express", "publication_date": "2006-10-30", "series_number": "22", "volume": "14", "issue": "22", "pages": "10410-10425" }, { "id": "authors:tegzg-n4t85", "collection": "authors", "collection_id": "tegzg-n4t85", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CHOoe06", "type": "article", "title": "Optical detection of asymmetric bacteria utilizing electro orientation", "author": [ { "family_name": "Choi", "given_name": "Jae-Woo", "clpid": "Choi-Jae-Woo" }, { "family_name": "Pu", "given_name": "Allen", "clpid": "Pu-Allen" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We propose a bacterial detection scheme which uses no biochemical markers and can be applied in a Point-of-Care setting. The detection scheme aligns asymmetric bacteria with an electric field and detects the optical scattering.", "doi": "10.1364/OE.14.009780", "issn": "1094-4087", "publisher": "Optical Society of America", "publication": "Optics Express", "publication_date": "2006-10-16", "series_number": "21", "volume": "14", "issue": "21", "pages": "9780-9785" }, { "id": "authors:kbsss-s2130", "collection": "authors", "collection_id": "kbsss-s2130", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CENjap06", "type": "article", "title": "Holographic capture of femtosecond pulse propagation", "author": [ { "family_name": "Centurion", "given_name": "Martin", "clpid": "Centurion-M" }, { "family_name": "Pu", "given_name": "Ye", "clpid": "Pu-Y" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We have implemented a holographic system to study the propagation of femtosecond laser pulses with high temporal (150 fs) and spatial resolutions (4 \u00b5m). The phase information in the holograms allows us to reconstruct both positive and negative index changes due to the Kerr nonlinearity (positive) and plasma formation (negative), and to reconstruct three-dimensional structure. Dramatic differences were observed in the interaction of focused femtosecond pulses with air, water, and carbon disulfide. The air becomes ionized in the focal region, while in water long plasma filaments appear before the light reaches a tight focus. In contrast, in carbon disulfide the optical beam breaks up into multiple filaments but no plasma is measured. We explain these different propagation regimes in terms of the different nonlinear material properties.", "doi": "10.1063/1.2345469", "issn": "0021-8979", "publisher": "Journal of Applied Physics", "publication": "Journal of Applied Physics", "publication_date": "2006-09-15", "series_number": "6", "volume": "100", "issue": "6", "pages": "Art. No. 063104" }, { "id": "authors:5n9c8-0re85", "collection": "authors", "collection_id": "5n9c8-0re85", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:TSAol06", "type": "article", "title": "Reflectionless evanescent-wave amplification by two dielectric planar waveguides", "author": [ { "family_name": "Tsang", "given_name": "Mankei", "clpid": "Tsang-M" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "Utilizing the underlying physics of evanescent-wave amplification by a negative-refractive-index slab, it is shown that evanescent waves with specific spatial frequencies can also be amplified without any reflection simply by two dielectric planar waveguides. The simple configuration allows one to take advantage of the high resolution limit of a high-refractive-index material without contact with the object.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "2006-09-15", "series_number": "18", "volume": "31", "issue": "18", "pages": "2741-2743" }, { "id": "authors:7jfg1-wh868", "collection": "authors", "collection_id": "7jfg1-wh868", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150325-110150114", "type": "article", "title": "Developing optofluidic technology through the fusion of microfluidics and optics", "author": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Quake", "given_name": "Stephen R.", "clpid": "Quake-S-R" }, { "family_name": "Yang", "given_name": "Changhuei", "orcid": "0000-0001-8791-0354", "clpid": "Yang-Changhuei" } ], "abstract": "We describe devices in which optics and fluidics are used synergistically to synthesize novel functionalities. Fluidic replacement or modification leads to reconfigurable optical systems, whereas the implementation of optics through the microfluidic toolkit gives highly compact and integrated devices. We categorize optofluidics according to three broad categories of interactions: fluid\u2013solid interfaces, purely fluidic interfaces and colloidal suspensions. We describe examples of optofluidic devices in each category.", "doi": "10.1038/nature05060", "issn": "0028-0836", "publisher": "Nature Publishing Group", "publication": "Nature", "publication_date": "2006-07-27", "series_number": "7101", "volume": "442", "issue": "7101", "pages": "381-386" }, { "id": "authors:w3va8-a2491", "collection": "authors", "collection_id": "w3va8-a2491", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CENprl06", "type": "article", "title": "Nonlinearity Management in Optics: Experiment, Theory, and Simulation", "author": [ { "family_name": "Centurion", "given_name": "Martin", "clpid": "Centurion-M" }, { "family_name": "Porter", "given_name": "Mason A.", "clpid": "Porter-M-A" }, { "family_name": "Kevrekidis", "given_name": "P. G.", "orcid": "0000-0002-7714-3689", "clpid": "Kevrekidis-P-G" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We conduct an experimental investigation of nonlinearity management in optics using femtosecond pulses and layered Kerr media consisting of glass and air. By examining the propagation properties over several diffraction lengths, we show that wave collapse can be prevented. We corroborate these experimental results with numerical simulations of the (2+1)-dimensional focusing cubic nonlinear Schr\u00f6dinger equation with piecewise constant coefficients and a theoretical analysis of this setting using a moment method.", "doi": "10.1103/PhysRevLett.97.033903", "issn": "0031-9007", "publisher": "American Physical Society", "publication": "Physical Review Letters", "publication_date": "2006-07-21", "series_number": "3", "volume": "97", "issue": "3", "pages": "Art. No. 033903" }, { "id": "authors:nm1wc-96b95", "collection": "authors", "collection_id": "nm1wc-96b95", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HSIao06", "type": "article", "title": "Beam-width-dependent filtering properties of strong volume holographic gratings", "author": [ { "family_name": "Hsieh", "given_name": "Hung-Te", "clpid": "Hsieh-Hung-Te" }, { "family_name": "Liu", "given_name": "Wenhai", "clpid": "Liu-Wenhai" }, { "family_name": "Havermeyer", "given_name": "Frank", "clpid": "Havermeyer-F" }, { "family_name": "Moser", "given_name": "Christophe", "clpid": "Moser-C" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "The finite dimension of the incident beam used to read out volume holographic gratings has interesting effects on their filtering properties. As the readout beam gets narrower, there is more deviation from the ideal response predicted for monochromatic plane waves. In this paper we experimentally explore beam-width-dependent phenomena such as wavelength selectivities, angular selectivities, and diffracted beam profiles. Volume gratings in both reflection and transmission geometries are investigated near 1550 nm. Numerical simulations utilizing the technique of Fourier decomposition provide a satisfactory explanation and confirm that the spread of spatial harmonics is the main contributing factor.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "2006-06-01", "series_number": "16", "volume": "45", "issue": "16", "pages": "3774-3780" }, { "id": "authors:s54m4-4ys03", "collection": "authors", "collection_id": "s54m4-4ys03", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ADLol06", "type": "article", "title": "Holographic grating formation in a colloidal suspension of silver nanoparticles", "author": [ { "family_name": "Adleman", "given_name": "James R.", "clpid": "Adleman-J-R" }, { "family_name": "Eggert", "given_name": "Helge A.", "clpid": "Eggert-H-A" }, { "family_name": "Buse", "given_name": "Karsten", "clpid": "Buse-K" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "Holographic gratings are recorded in colloidal suspensions of silver nanoparticles by utilizing interfering nanosecond pulses. The diffraction efficiency is measured with continuous-wave light. An instantaneous response together with a transient grating are observed: the nanoparticles absorb the pump light and heat up. Heat is transferred to the solvent, and a delayed thermal grating appears. The final decay time constant of this grating depends quadratically on the period length and has a typical value of 1 \u00b5s for grating spacings of several micrometers.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "2006-02-15", "series_number": "4", "volume": "31", "issue": "4", "pages": "447-449" }, { "id": "authors:me59d-cw160", "collection": "authors", "collection_id": "me59d-cw160", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LIZoe06", "type": "article", "title": "Single mode optofluidic distributed feedback dye laser", "author": [ { "family_name": "Li", "given_name": "Zhenyu", "clpid": "Li-Zhenyu" }, { "family_name": "Zhang", "given_name": "Zhaoyu", "clpid": "Zhang-Zhaoyu" }, { "family_name": "Emery", "given_name": "Teresa", "clpid": "Emery-T-H" }, { "family_name": "Scherer", "given_name": "Axel", "orcid": "0000-0002-2160-9064", "clpid": "Scherer-A" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "Single frequency lasing from organic dye solutions on a monolithic poly(dimethylsiloxane) (PDMS) elastomer chip is demonstrated. The laser cavity consists of a single mode liquid core/PDMS cladding channel waveguide and a phase shifted 15th order distributed feedback (DFB) structure. A 1mM solution of Rhodamine 6G in a methanol and ethylene glycol mixture was used as the gain medium. Using 6 nanosecond 532nm Nd:YAG laser pulses as the pump light, we achieved threshold pump fluence of ~0.8mJ/cm2 and single-mode operation at pump levels up to ten times the threshold. This microfabricated dye laser provides a compact and inexpensive coherent light source for microfluidics and integrated optics covering from near UV to near IR spectral region.", "issn": "1094-4087", "publisher": "Optical Society of America", "publication": "Optics Express", "publication_date": "2006-01-23", "series_number": "2", "volume": "14", "issue": "2", "pages": "696-701" }, { "id": "authors:e1vsd-8dw90", "collection": "authors", "collection_id": "e1vsd-8dw90", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:TSApra06.981", "type": "article", "title": "Propagation of temporal entanglement", "author": [ { "family_name": "Tsang", "given_name": "Mankei", "clpid": "Tsang-M" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "The equations that govern the temporal evolution of two photons in the Schr\u00f6dinger picture are derived, taking into account the effects of loss, group-velocity dispersion, temporal phase modulation, linear coupling among different optical modes, and four-wave mixing. Inspired by the formalism, we propose the concept of quantum temporal imaging, which uses dispersive elements and temporal phase modulators to manipulate the temporal correlation of two entangled photons. We also present the exact solution of a two-photon vector soliton, in order to demonstrate the ease of use and intuitiveness of the proposed formulation.", "doi": "10.1103/PhysRevA.73.013822", "issn": "1050-2947", "publisher": "Physical Review A", "publication": "Physical Review A", "publication_date": "2006-01-01", "series_number": "1", "volume": "73", "issue": "1", "pages": "Art. no. 013822" }, { "id": "authors:xm9qy-0e252", "collection": "authors", "collection_id": "xm9qy-0e252", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ERIol06", "type": "article", "title": "Nanofluidic tuning of photonic crystal circuits", "author": [ { "family_name": "Erickson", "given_name": "David", "clpid": "Erickson-D" }, { "family_name": "Rockwood", "given_name": "Troy", "clpid": "Rockwood-T" }, { "family_name": "Emery", "given_name": "Teresa", "clpid": "Emery-T" }, { "family_name": "Scherer", "given_name": "Axel", "orcid": "0000-0002-2160-9064", "clpid": "Scherer-A" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "By integrating soft-lithography-based nanofluidics with silicon nanophotonics, we demonstrate dynamic, liquid-based addressing and high Delta n/n(~0.1) refractive index modulation of individual features within photonic structures at subwavelength length scales. We show ultracompact tunable spectral filtering through nanofluidic targeting of a single row of holes within a planar photonic crystal. We accomplished this with an optofluidic integration architecture comprising a nanophotonic layer, a nanofluidic delivery structure, and a microfluidic control engine. Variants of this technique could enable dynamic reconfiguration of photonic circuits, selective introduction of optical nonlinearities, or delivery of single molecules into resonant cavities for biodetection.", "issn": "0146-9592", "publisher": "Optical Society of America", "publication": "Optics Letters", "publication_date": "2006-01-01", "series_number": "1", "volume": "31", "issue": "1", "pages": "59-61" }, { "id": "authors:0nxcv-19g10", "collection": "authors", "collection_id": "0nxcv-19g10", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:TIAjosaa05", "type": "article", "title": "Diffraction from deformed volume holograms: perturbation theory approach", "author": [ { "family_name": "Tian", "given_name": "Kehan", "clpid": "Tian-Kehan" }, { "family_name": "Cuingnet", "given_name": "Thomas", "clpid": "Cuingnet-T" }, { "family_name": "Li", "given_name": "Zhenyu", "clpid": "Li-Zhenyu" }, { "family_name": "Liu", "given_name": "Wenhai", "clpid": "Liu-Wenhai" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Barbastathis", "given_name": "George", "clpid": "Barbastathis-G" } ], "abstract": "We derive the response of a volume grating to arbitrary small deformations, using a perturbative approach. This result is of interest for two applications: (a) when a deformation is undesirable and one seeks to minimize the diffracted field's sensitivity to it and (b) when the deformation itself is the quantity of interest and the diffracted field is used as a probe into the deformed volume where the hologram was originally recorded. We show that our result is consistent with previous derivations motivated by the phenomenon of shrinkage in photopolymer holographic materials. We also present the analysis of the grating's response to deformation due to a point indenter and present experimental results consistent with theory.", "issn": "1084-7529", "publisher": "Optical Society of America", "publication": "Journal of the Optical Society of America A", "publication_date": "2005-12", "series_number": "12", "volume": "22", "issue": "12", "pages": "2880-2889" }, { "id": "authors:esg0h-zwp53", "collection": "authors", "collection_id": "esg0h-zwp53", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HSIol05", "type": "article", "title": "Femtosecond holography in lithium niobate crystals", "author": [ { "family_name": "Hsieh", "given_name": "Hung-Te", "clpid": "Hsieh-Hung-Te" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Beyer", "given_name": "Oliver", "clpid": "Beyer-O" }, { "family_name": "Maxein", "given_name": "Dominik", "clpid": "Maxein-D" }, { "family_name": "von Korff Schmising", "given_name": "Clemens", "clpid": "von-Korff-Schmising-C" }, { "family_name": "Buse", "given_name": "Karsten", "clpid": "Buse-K" }, { "family_name": "Sturman", "given_name": "Boris", "clpid": "Sturman-B" } ], "abstract": "Spatial gratings are recorded holographically by two femtosecond pump pulses at 388 nm in lithium niobate (LiNbO3) crystals and read out by a Bragg-matched, temporally delayed probe pulse at 776 nm. We claim, to our knowledge, the first holographic pump-probe experiments with subpicosecond temporal resolution for LiNbO3. An instantaneous grating that is due mostly to the Kerr effect as well as a long-lasting grating that results mainly from the absorption caused by photoexcited carriers was observed. The Kerr coefficient of LiNbO3 for our experimental conditions, i.e., pumped and probed at different wavelengths, was approximately 1.0\u00d710^-5 cm\u00b2/GW.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "2005-09-01", "series_number": "17", "volume": "30", "issue": "17", "pages": "2233-2235" }, { "id": "authors:623w3-dp988", "collection": "authors", "collection_id": "623w3-dp988", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CENoe05", "type": "article", "title": "Self-organization of spatial solitons", "author": [ { "family_name": "Centurion", "given_name": "Martin", "clpid": "Centurion-M" }, { "family_name": "Pu", "given_name": "Ye", "clpid": "Pu-Y" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We present experimental results on the transverse modulation instability of an elliptical beam propagating in a bulk nonlinear Kerr medium, and the formation and self-organization of spatial solitons. We have observed the emergence of order, self organization and a transition to an unstable state. Order emerges through the formation of spatial solitons in a periodic array. If the initial period of the array is unstable the solitons will tend to self-organize into a larger (more stable) period. Finally the system transitions to a disordered state where most of the solitons disappear and the beam profile becomes unstable to small changes in the input energy.", "issn": "1094-4087", "publisher": "Optical Society of America", "publication": "Optics Express", "publication_date": "2005-08-08", "series_number": "16", "volume": "13", "issue": "16", "pages": "6202-6211" }, { "id": "authors:eg4s1-zjv18", "collection": "authors", "collection_id": "eg4s1-zjv18", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:KOSao05", "type": "article", "title": "Holography in commercially available photoetchable glasses", "author": [ { "family_name": "K\u00f6sters", "given_name": "Michael", "clpid": "K\u00f6sters-Michael" }, { "family_name": "Hsieh", "given_name": "Hung-Te", "clpid": "Hsieh-Hung-Te" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Buse", "given_name": "Karsten", "clpid": "Buse-K" } ], "abstract": "Volume holographic gratings are recorded and retrieved in two commercially available glasses: Schott Foturan and Hoya PEG3. These materials are photoetchable, which describes their major application, but they also allow storage of volume holograms without any chemical etching. The samples are illuminated with ultraviolet light at a wavelength of 325 nm and thermally processed to achieve a maximum diffraction efficiency of approximately 9% for a 1-mm-thick sample. The two glasses show similar behavior; the diffraction efficiencies in Foturan tend to be slightly larger, whereas PEG3 tends to have weaker light scattering.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "2005-06-10", "series_number": "17", "volume": "44", "issue": "17", "pages": "3399-3402" }, { "id": "authors:8zz51-x3p54", "collection": "authors", "collection_id": "8zz51-x3p54", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BEYol05", "type": "article", "title": "Femtosecond time-resolved absorption processes in lithium niobate crystals", "author": [ { "family_name": "Beyer", "given_name": "O.", "clpid": "Beyer-O" }, { "family_name": "Maxein", "given_name": "D.", "clpid": "Maxein-D" }, { "family_name": "Buse", "given_name": "K.", "clpid": "Buse-K" }, { "family_name": "Sturman", "given_name": "B.", "clpid": "Sturman-B" }, { "family_name": "Hsieh", "given_name": "H. T.", "clpid": "Hsieh-Hung-Te" }, { "family_name": "Psaltis", "given_name": "D.", "clpid": "Psaltis-D" } ], "abstract": "emtosecond pump pulses are strongly attenuated in lithium niobate owing to two-photon absorption; the relevant nonlinear coefficient beta_p ranges from ~3.5 cm/GW for lambda_p = 388 nm to ~0.1 cm/GW for 514 nm. In collinear pump-probe experiments the probe transmission at the double pump wavelength 2lambda_p=776 nm is controlled by two different processes: A direct absorption process involving pump and probe photons (beta_r ~ or = 0.9 cm/GW) leads to a pronounced short-duration transmission dip, whereas the probe absorption by pump-excited charge carriers results in a long-duration plateau. Coherent pump-probe interactions are of no importance. Hot-carrier relaxation occurs on the time scale of < or ~0.1 ps.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "2005-06-01", "series_number": "11", "volume": "30", "issue": "11", "pages": "1366-1368" }, { "id": "authors:pv2sf-a2z13", "collection": "authors", "collection_id": "pv2sf-a2z13", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HSIjap05", "type": "article", "title": "Enhanced temporal resolution in femtosecond dynamic-grating experiments", "author": [ { "family_name": "Hsieh", "given_name": "Hung-Te", "clpid": "Hsieh-Hung-Te" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Beyer", "given_name": "Oliver", "clpid": "Beyer-O" }, { "family_name": "Maxein", "given_name": "Dominik", "clpid": "Maxein-D" }, { "family_name": "Buse", "given_name": "Karsten", "clpid": "Buse-K" }, { "family_name": "Sturman", "given_name": "Boris", "clpid": "Sturman-B" } ], "abstract": "Recording of gratings by interference of two pump pulses and diffraction of a third probe pulse is useful for investigating ultrafast material phenomena. We demonstrate, in theory and experiment, that the temporal resolution in such configurations does not degrade appreciably even for large angular separation between the pump pulses. Transient Kerr gratings are generated inside calcium fluoride (CaF2) crystals by two interfering femtosecond (pump) pulses at 388 nm and read out by a Bragg-matched probe pulse at 776 nm. The solution to the relevant coupled-mode equations is well corroborated by the experimental results, yielding a value of the Kerr coefficient of ~ 4.4\u00d710^(\u20137) cm^2/GW for CaF2.", "doi": "10.1063/1.1927277", "issn": "0021-8979", "publisher": "Journal of Applied Physics", "publication": "Journal of Applied Physics", "publication_date": "2005-06-01", "series_number": "11", "volume": "97", "issue": "11", "pages": "Art. No. 113107" }, { "id": "authors:kx7a1-66x15", "collection": "authors", "collection_id": "kx7a1-66x15", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CENpra05", "type": "article", "title": "Dynamics of filament formation in a Kerr medium", "author": [ { "family_name": "Centurion", "given_name": "Martin", "clpid": "Centurion-M" }, { "family_name": "Pu", "given_name": "Ye", "clpid": "Pu-Y" }, { "family_name": "Tsang", "given_name": "Mankei", "clpid": "Tsang-M" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We have studied the large-scale beam breakup and filamentation of femtosecond pulses in a Kerr medium. We have experimentally monitored the formation of stable light filaments, conical emission, and interactions between filaments. Three major stages lead to the formation of stable light filaments: First the beam breaks up into a pattern of connected lines (constellation), then filaments form on the constellations, and finally the filaments release a fraction of their energy through conical emission. We observed a phase transition to a faster filamentation rate at the onset of conical emission. We attribute this to the interaction of conical emissions with the constellation which creates additional filaments. Numerical simulations show good agreement with the experimental results.", "doi": "10.1103/PhysRevA.71.063811", "issn": "1050-2947", "publisher": "Physical Review A", "publication": "Physical Review A", "publication_date": "2005-06-01", "series_number": "6", "volume": "71", "issue": "6", "pages": "Art. no. 063811" }, { "id": "authors:x040q-k5t43", "collection": "authors", "collection_id": "x040q-k5t43", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BEYpre05", "type": "article", "title": "Investigation of nonlinear absorption processes with femtosecond light pulses in lithium niobate crystals", "author": [ { "family_name": "Beyer", "given_name": "O.", "clpid": "Beyer-O" }, { "family_name": "Maxein", "given_name": "D.", "clpid": "Maxein-D" }, { "family_name": "Buse", "given_name": "K.", "clpid": "Buse-K" }, { "family_name": "Sturman", "given_name": "B.", "clpid": "Sturman-B" }, { "family_name": "Hsieh", "given_name": "H. T.", "clpid": "Hsieh-Hung-Te" }, { "family_name": "Psaltis", "given_name": "D.", "clpid": "Psaltis-D" } ], "abstract": "The propagation of high-power femtosecond light pulses in lithium niobate crystals (LiNbO3) is investigated experimentally and theoretically in collinear pump-probe transmission experiments. It is found within a wide intensity range that a strong decrease of the pump transmission coefficient at wavelength 388 nm fully complies with the model of two-photon absorption; the corresponding nonlinear absorption coefficient is betap~=3.5 cm/GW. Furthermore, strong pump pulses induce a considerable absorption for the probe at 776 nm. The dependence of the probe transmission coefficient on the time delay Deltat between probe and pump pulses is characterized by a narrow dip (at Deltat~=0) and a long (on the picosecond time scale) lasting plateau. The dip is due to direct two-photon transitions involving pump and probe photons; the corresponding nonlinear absorption coefficient is betar~=0.9 cm/GW. The plateau absorption is caused by the presence of pump-excited charge carriers; the effective absorption cross section at 776 nm is sigmar~=8\u00d710^\u201318 cm^2. The above nonlinear absorption parameters are not strongly polarization sensitive. No specific manifestations of the relaxation of hot carriers are found for a pulse duration of ~=0.24 ps.", "doi": "10.1103/PhysRevE.71.056603", "issn": "1539-3755", "publisher": "Physical Review E", "publication": "Physical Review E", "publication_date": "2005-05", "series_number": "5", "volume": "71", "issue": "5", "pages": "Art. No. 056603" }, { "id": "authors:wg9yz-xwf82", "collection": "authors", "collection_id": "wg9yz-xwf82", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:TSApra05", "type": "article", "title": "Spontaneous spectral phase conjugation for coincident frequency entanglement", "author": [ { "family_name": "Tsang", "given_name": "Mankei", "clpid": "Tsang-M" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "Spontaneous parametric processes pumped transversely with short pulses are studied under a unified framework, which proves that such processes can efficiently generate entangled photon pairs with time anticorrelation and frequency correlation. Improvements upon previously proposed schemes can be made by the use of quasi-phase-matching, four-wave mixing, and cross-phase-modulation compensation. The use of frequency-correlated photons in the Hung-Ou-Mandel interferometer is studied.", "doi": "10.1103/PhysRevA.71.043806", "issn": "1050-2947", "publisher": "Physical Review A", "publication": "Physical Review A", "publication_date": "2005-04-01", "series_number": "4", "volume": "71", "issue": "4", "pages": "Art. no. 043806" }, { "id": "authors:ky15j-6pn55", "collection": "authors", "collection_id": "ky15j-6pn55", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CAMapl04", "type": "article", "title": "A microfluidic 2\u00d72 optical switch", "author": [ { "family_name": "Campbell", "given_name": "Kyle", "clpid": "Campbell-K" }, { "family_name": "Groisman", "given_name": "Alex", "clpid": "Groisman-A" }, { "family_name": "Levy", "given_name": "Uriel", "clpid": "Levy-U" }, { "family_name": "Pang", "given_name": "Lin", "clpid": "Pang-L" }, { "family_name": "Mookherjea", "given_name": "Shayan", "clpid": "Mookherjea-S" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Fainman", "given_name": "Yeshaiahu", "clpid": "Fainman-Y" } ], "abstract": "A 2\u00d72 microfluidic-based optical switch is proposed and demonstrated. The switch is made of an optically clear silicon elastomer, Polydimethylsiloxane (PDMS), using soft lithography. It has insertion loss smaller than 1 dB and extinction ratio on the order of 20 dB. The device is switching between transmission (bypass) and reflection (exchange) modes within less than 20 ms", "doi": "10.1063/1.1839281", "issn": "0003-6951", "publisher": "Applied Physics Letters", "publication": "Applied Physics Letters", "publication_date": "2004-12-20", "series_number": "25", "volume": "85", "issue": "25", "pages": "6119-6121" }, { "id": "authors:vned0-vcm61", "collection": "authors", "collection_id": "vned0-vcm61", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170123-154140590", "type": "article", "title": "Imaging using volume holograms", "author": [ { "family_name": "Sinha", "given_name": "Arnab", "orcid": "0000-0002-7122-3549", "clpid": "Sinha-A" }, { "family_name": "Barbastathis", "given_name": "George", "clpid": "Barbastathis-G" }, { "family_name": "Liu", "given_name": "Wenhai", "clpid": "Liu-Wenhai" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We present an overview of imaging systems that incorporate a volume hologram as one of the optical field processing elements in the system. We refer to these systems as volume holographic imaging (VHI) systems. The volume hologram is recorded just once, and the recording parameters depend on the functional requirements of the imaging system. The recording step offers great flexibility in designing application-specific imaging systems. We discuss how a VHI system can be configured for diverse imaging applications ranging from surface profilometry to real-time hyperspectral microscopy, and summarize recent developments in this field.", "doi": "10.1117/1.1775230", "issn": "0091-3286", "publisher": "Society of Photo-Optical Instrumentation Engineers", "publication": "Optical Engineering", "publication_date": "2004-09", "series_number": "9", "volume": "43", "issue": "9", "pages": "1959-1972" }, { "id": "authors:dzc1v-f0808", "collection": "authors", "collection_id": "dzc1v-f0808", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170124-101017298", "type": "article", "title": "Volume holographic grating-based continuously tunable optical filter", "author": [ { "family_name": "Havermeyer", "given_name": "Frank", "clpid": "Havermeyer-F" }, { "family_name": "Liu", "given_name": "Wenhai", "clpid": "Liu-Wenhai" }, { "family_name": "Moser", "given_name": "Christophe", "clpid": "Moser-C" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Steckman", "given_name": "Gregory J.", "clpid": "Steckman-G-J" } ], "abstract": "We propose and demonstrate a widely tunable optical filter, realized by angle tuning a volume holographic grating. The volume holographic grating selectively drops a narrow portion of the signal bandwidth into a fiber while passing through the rest of the signals. The demonstrated 1510- to 1590-nm tuning range covers the entire erbium-doped fiber amplifier (EDFA) C band, with small bandwidth variation and low insertion loss (<1 dB). Group delay, polarization-dependent loss, and polarization mode dispersion are measured and investigated for optimizing the filter characteristics.", "doi": "10.1117/1.1773775", "issn": "0091-3286", "publisher": "Society of Photo-Optical Instrumentation Engineers", "publication": "Optical Engineering", "publication_date": "2004-09", "series_number": "9", "volume": "43", "issue": "9", "pages": "2017-2021" }, { "id": "authors:4epq2-y4w35", "collection": "authors", "collection_id": "4epq2-y4w35", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:MAUapl04", "type": "article", "title": "Liquid-crystal electric tuning of a photonic crystal laser", "author": [ { "family_name": "Maune", "given_name": "Brett", "clpid": "Maune-B" }, { "family_name": "Lon\u010dar", "given_name": "Marko", "clpid": "Lon\u010dar-M" }, { "family_name": "Witzens", "given_name": "Jeremy", "clpid": "Witzens-J" }, { "family_name": "Hochberg", "given_name": "Michael", "clpid": "Hochberg-M" }, { "family_name": "Baehr-Jones", "given_name": "Thomas", "clpid": "Baehr-Jones-T" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Scherer", "given_name": "Axel", "orcid": "0000-0002-2160-9064", "clpid": "Scherer-A" } ], "abstract": "An electrically tuned nematic liquid-crystal (LC) infiltrated photonic crystal (PC) laser is demonstrated. This PC laser represents an emerging class of nanoscale optical adaptive devices enabled by the convergence of nonlinear optical materials, electronics, and fluidics that promise increased functionality and utility over existing technologies. A LC cell is constructed by encasing the PC laser between two indium tin oxide glass plates, which serve as the modulating electrodes. Applying a voltage across the cell realigns the LC, modifies the laser cavity's optical path length, and blueshifts the lasing wavelength.", "doi": "10.1063/1.1772869", "issn": "0003-6951", "publisher": "Applied Physics Letters", "publication": "Applied Physics Letters", "publication_date": "2004-07-19", "series_number": "3", "volume": "85", "issue": "3", "pages": "360-362" }, { "id": "authors:rv286-hmf92", "collection": "authors", "collection_id": "rv286-hmf92", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LIUao04", "type": "article", "title": "Volume Holographic Hyperspectral Imaging", "author": [ { "family_name": "Liu", "given_name": "Wenhai", "clpid": "Liu-Wenhai" }, { "family_name": "Barbastathis", "given_name": "George", "clpid": "Barbastathis-G" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "A volume hologram has two degenerate Bragg-phase-matching dimensions and provides the capability of volume holographic imaging. We demonstrate two volume holographic imaging architectures and investigate their imaging resolution, aberration, and sensitivity. The first architecture uses the hologram directly as an objective imaging element where strong aberration is observed and confirmed by simulation. The second architecture uses an imaging lens and a transmission geometry hologram to achieve linear two-dimensional optical sectioning and imaging of a four-dimensional (spatial plus spectral dimensions) object hyperspace. Multiplexed holograms can achieve simultaneously three-dimensional imaging of an object without a scanning mechanism.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "2004-06-20", "series_number": "18", "volume": "43", "issue": "18", "pages": "3581-3599" }, { "id": "authors:gbcr9-4e969", "collection": "authors", "collection_id": "gbcr9-4e969", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:TSAoe04", "type": "article", "title": "Spectral phase conjugation with cross-phase modulation compensation", "author": [ { "family_name": "Tsang", "given_name": "Mankei", "clpid": "Tsang-M" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "Spectral phase conjugation with short pump pulses in a third-order nonlinear material is analyzed in depth. It is shown that if signal amplification is considered, the conversion efficiency can be significantly higher than previously considered, while the spectral phase conjugation operation remains accurate. A novel method of compensating for cross-phase modulation, the main parasitic effect, is also proposed. The validity of our theory and the performance of the spectral phase conjugation scheme are studied numerically.", "issn": "1094-4087", "publisher": "Optical Society of America", "publication": "Optics Express", "publication_date": "2004-05-17", "series_number": "10", "volume": "12", "issue": "10", "pages": "2207-2219" }, { "id": "authors:k8myn-w6385", "collection": "authors", "collection_id": "k8myn-w6385", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CENol04", "type": "article", "title": "Holographic recording of laser-induced plasma", "author": [ { "family_name": "Centurion", "given_name": "Martin", "clpid": "Centurion-M" }, { "family_name": "Pu", "given_name": "Ye", "clpid": "Pu-Ye" }, { "family_name": "Liu", "given_name": "Zhiwen", "clpid": "Liu-Zhiwen" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "H\u00e4nsch", "given_name": "Theodor W.", "clpid": "H\u00e4nsch-T-W" } ], "abstract": "We report on a holographic probing technique that allows for measurement of free-electron distribution with fine spatial detail. Plasma is generated by focusing a femtosecond pulse in air. We also demonstrate the capability of the holographic technique of capturing the time evolution of the plasma-generation process.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "2004-04-01", "series_number": "7", "volume": "29", "issue": "7", "pages": "772-774" }, { "id": "authors:qp842-69y38", "collection": "authors", "collection_id": "qp842-69y38", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190320-150103119", "type": "article", "title": "Athermal Holographic Filters", "author": [ { "family_name": "Hsieh", "given_name": "Hung-Te", "clpid": "Hsieh-Hung-Te" }, { "family_name": "Panotopoulos", "given_name": "George", "clpid": "Panotopoulos-G" }, { "family_name": "Liger", "given_name": "Matthieu", "clpid": "Liger-M" }, { "family_name": "Tai", "given_name": "Yu-Chong", "orcid": "0000-0001-8529-106X", "clpid": "Tai-Yu-Chong" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "This letter presents the theory and experimental results of an athermal holographic filter design employing a thermally actuated microelectromechanical system mirror to compensate for the drift of Bragg wavelength due to changes of temperature. The center wavelength of our holographic filter is shown to remain constant from 21\u00b0C to 60\u00b0C.", "doi": "10.1109/lpt.2003.820483", "issn": "1041-1135", "publisher": "IEEE", "publication": "IEEE Photonics Technology Letters", "publication_date": "2004-01", "series_number": "1", "volume": "16", "issue": "1", "pages": "177-179" }, { "id": "authors:9hqj8-mr980", "collection": "authors", "collection_id": "9hqj8-mr980", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:TSAol03a", "type": "article", "title": "Reverse propagation of femtosecond pulses in optical fibers", "author": [ { "family_name": "Tsang", "given_name": "Mankei", "clpid": "Tsang-M" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Omenetto", "given_name": "Fiorenzo G.", "clpid": "Omenetto-F-G" } ], "abstract": "We present a numerical technique for reversing femtosecond pulse propagation in an optical fiber, such that given any output pulse it is possible to obtain the input pulse shape by numerically undoing all dispersion and nonlinear effects. The technique is tested against experimental results, and it is shown that it can be used for fiber output pulse optimization in both the anomalous and normal dispersion regimes.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "2003-10-15", "series_number": "20", "volume": "28", "issue": "20", "pages": "1873-1875" }, { "id": "authors:8hyak-nz505", "collection": "authors", "collection_id": "8hyak-nz505", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:TSAol03b", "type": "article", "title": "Dispersion and nonlinearity compensation by spectral phase conjugation", "author": [ { "family_name": "Tsang", "given_name": "Mankei", "clpid": "Tsang-M" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We propose the use of spectral phase conjugation to compensate for dispersion of all orders, self-phase modulation, and self-steepening of an optical pulse in a fiber. Although this method cannot compensate for loss and intrapulse Raman scattering, it is superior to the previously suggested midway temporal phase conjugation method if high-order dispersion is a main source of distortion. The reshaping performance of our proposed scheme and a combined temporal and spectral phase conjugation scheme in the presence of uncompensated effects is studied numerically.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "2003-09-01", "series_number": "17", "volume": "28", "issue": "17", "pages": "1558-1560" }, { "id": "authors:a3hc1-tkc13", "collection": "authors", "collection_id": "a3hc1-tkc13", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:YANjosab03", "type": "article", "title": "Photorefractive properties of lithium niobate crystals doped with manganese", "author": [ { "family_name": "Yang", "given_name": "Yunping", "clpid": "Yang-Y" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Luennemann", "given_name": "Marc", "clpid": "Luennemann-M" }, { "family_name": "Berben", "given_name": "Dirk", "clpid": "Berben-D" }, { "family_name": "Hartwig", "given_name": "Ulrich", "clpid": "Hartwig-U" }, { "family_name": "Buse", "given_name": "Karsten", "clpid": "Buse-K" } ], "abstract": "The photorefractive properties of lithium niobate crystals doped with manganese (Mn) have been investigated. It is found that the effect of dark decay due to electron tunneling, which is the limiting factor of the highest practical doping level, is less in LiNbO_3:Mn than in LiNbO_3:Fe , and higher doping levels can be used in LiNbO_3:Mn to achieve larger dynamic range and sensitivity for holographic applications. The highest practical doping level in LiNbO_3:Mn has been found to be ~0.5 wt.% MnCO_3, and refractive-index changes and sensitivities up to 1.5X10^-3 and 1.3 cm/J are measured for extraordinarily polarized light of the wavelength 458 nm. It has been found that, in terms of both dynamic range (or refractive-index change) and sensitivity, the optimal oxidation state is highly oxidized. The distribution coefficient of Mn has been determined to be ~1. Absorption measurements are used to obtain more information about charge-transport parameters. The material is excellently suited for holographic recording with blue light. The hologram quality is outstanding because holographic scattering is much weaker compared with that in, e.g., iron-doped lithium niobate. Thermal fixing has been successfully demonstrated in LiNbO_3:Mn crystals.", "issn": "0740-3224", "publisher": "Optical Society of America", "publication": "Journal of the Optical Society of America B", "publication_date": "2003-07", "series_number": "7", "volume": "20", "issue": "7", "pages": "1491-1502" }, { "id": "authors:2ae71-gpy18", "collection": "authors", "collection_id": "2ae71-gpy18", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:YANao03", "type": "article", "title": "Comparison of Transmission and the 90-Degree Holographic Recording Geometry", "author": [ { "family_name": "Yang", "given_name": "Yunping", "clpid": "Yang-Y" }, { "family_name": "Adibi", "given_name": "Ali", "clpid": "Adibi-A" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We compare the system performances of two holographic recording geometries using iron-doped lithium niobate: the 90-degree and transmission geometry. We find that transmission geometry is better because the attainable dynamic range (M/#) is much higher. The only drawback of transmission geometry is the buildup of fanning, particularly during readout. Material solutions that reduce fanning such as doubly-doped photorefractive crystals make transmission geometry the clear winner.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "2003-06-10", "series_number": "17", "volume": "42", "issue": "17", "pages": "3418-3427" }, { "id": "authors:qh02q-84v74", "collection": "authors", "collection_id": "qh02q-84v74", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:MOSol03", "type": "article", "title": "Folded shift multiplexing", "author": [ { "family_name": "Moser", "given_name": "Christophe", "clpid": "Moser-C" }, { "family_name": "Liu", "given_name": "Wenhai", "clpid": "Liu-Wenhai" }, { "family_name": "Fainman", "given_name": "Yeshaiahu", "clpid": "Fainman-Yeshaiahu" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "Shift multiplexing is a holographic recording method that uses a spherical reference wave. We extend the principle to a thin slab of holographic material that acts as a waveguide. Total internal reflection folds the reference spherical beam in one dimension. We demonstrate that the shift selectivity with the folded spherical beam is independent of the slab thickness but depends instead on the numerical aperture of the coupled spherical wave. A shift selectivity of 0.5 \u00b5m has been achieved with a 1-mm-thick LiNbO3 crystal and 50 high-definition data pages are recorded with this method.", "issn": "0146-9592", "publisher": "Optical Society of America", "publication": "Optics Letters", "publication_date": "2003-06-01", "series_number": "11", "volume": "28", "issue": "11", "pages": "899-901" }, { "id": "authors:9f7ej-qye08", "collection": "authors", "collection_id": "9f7ej-qye08", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141117-093940989", "type": "article", "title": "Coherent Optical Information Systems", "author": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "Coherent optical beams are used to communicate, store, and process information in a growing number of applications. The availability of coherent laser sources is of critical importance for the realization of such optical information systems. An incoherent source randomly populates the available temporal and spatial channels of the optical system, making it difficult to represent information. Coherent laser sources provide a stable carrier on which to encode information, making it possible to realize powerful information-processing techniques such as wavelength division multiplexing in fiber networks, gated holographic imaging, and three-dimensional optical data storage.", "doi": "10.1126/science.1078823", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "2002-11-15", "series_number": "5597", "volume": "298", "issue": "5597", "pages": "1359-1363" }, { "id": "authors:n8863-s8k76", "collection": "authors", "collection_id": "n8863-s8k76", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:PANjap02", "type": "article", "title": "Temperature dependence of absorption in photorefractive iron-doped lithium niobate crystals", "author": [ { "family_name": "Panotopoulos", "given_name": "G.", "clpid": "Panotopoulos-G" }, { "family_name": "Luennemann", "given_name": "M.", "clpid": "Luennemann-M" }, { "family_name": "Buse", "given_name": "K.", "clpid": "Buse-K" }, { "family_name": "Psaltis", "given_name": "D.", "clpid": "Psaltis-D" } ], "abstract": "We present experimental data showing a significant dependence of light absorption on temperature in photorefractive LiNbO3:Fe crystals. The results are successfully explained by assuming that the widths of the Fe2+ absorption bands in the visible and in the infrared spectral region depend on temperature. The findings are of relevance for thermal fixing of holograms. Furthermore, a temperature-induced increase of the infrared absorption is promising for improved infrared recording.", "doi": "10.1063/1.1486257", "issn": "0021-8979", "publisher": "Journal of Applied Physics", "publication": "Journal of Applied Physics", "publication_date": "2002-07-15", "series_number": "2", "volume": "92", "issue": "2", "pages": "793-796" }, { "id": "authors:swgpb-9nf67", "collection": "authors", "collection_id": "swgpb-9nf67", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BITapl02", "type": "article", "title": "Dark decay of holograms in photorefractive polymers", "author": [ { "family_name": "Bittner", "given_name": "Reinhard", "clpid": "Bittner-R" }, { "family_name": "Meerholz", "given_name": "Klaus", "clpid": "Meerhold-K" }, { "family_name": "Steckman", "given_name": "Gregory", "clpid": "Steckman-G-J" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "The decay of holograms stored in photorefractive polymer composites based on poly(N-vinyl-carbazole) with and without extrinsic deep traps is investigated. The photorefractive phase shift is identified as one of the key parameters determining the dark decay dynamics. This has important implications for all kinds of photorefractive imaging applications including holographic data storage. A trade off will be required between accepting a certain degree of hologram distortion due to two-beam coupling on the one hand and achieving high hologram stability during idle periods in the dark with the external field applied on the other.", "doi": "10.1063/1.1492848", "issn": "0003-6951", "publisher": "Applied Physics Letters", "publication": "Applied Physics Letters", "publication_date": "2002-07-08", "series_number": "2", "volume": "81", "issue": "2", "pages": "211-213" }, { "id": "authors:8qwbd-tqj43", "collection": "authors", "collection_id": "8qwbd-tqj43", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LIUol02a", "type": "article", "title": "Real-time spectral imaging in three spatial dimensions", "author": [ { "family_name": "Liu", "given_name": "Wenhai", "clpid": "Liu-Wenhai" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Barbastathis", "given_name": "George", "clpid": "Barbastathis-G" } ], "abstract": "We report what is to our knowledge the first volume-holographic optical imaging instrument with the capability to return three-dimensional spatial as well as spectral information about semitranslucent microscopic objects in a single measurement. The four-dimensional volume-holographic microscope is characterized theoretically and experimentally by use of fluorescent microspheres as objects.", "doi": "10.1364/OL.27.000854", "issn": "0146-9592", "publisher": "Optical Society of America", "publication": "Optics Letters", "publication_date": "2002-05-15", "series_number": "10", "volume": "27", "issue": "10", "pages": "854-856" }, { "id": "authors:gav9d-etw49", "collection": "authors", "collection_id": "gav9d-etw49", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LIUapl02", "type": "article", "title": "Holographic recording of fast phenomena", "author": [ { "family_name": "Liu", "given_name": "Zhiwen", "clpid": "Liu-Zhiwen" }, { "family_name": "Steckman", "given_name": "Gregory J.", "clpid": "Steckman-G-J" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We report on a holographic method for recording fast events whose speed is limited by the laser pulse duration if the recording material has sufficient sensitivity to reliably record a frame of the fast event with a single pulse. The method we describe uses the angular selectivity of thick holograms to resolve frames that are recorded with adjacent pulses. Two specially designed cavities are used to generate the signal and reference pulse trains. We experimentally demonstrate the system by recording laser induced shock waves with a temporal resolution of 5.9 ns, limited by the pulse width of the Q-switched Nd:yttrium\u2013aluminum\u2013garnet laser used in the experiments.", "doi": "10.1063/1.1446205", "issn": "0003-6951", "publisher": "Applied Physics Letters", "publication": "Applied Physics Letters", "publication_date": "2002-02-04", "series_number": "5", "volume": "80", "issue": "5", "pages": "731-733" }, { "id": "authors:gmhxv-b2g87", "collection": "authors", "collection_id": "gmhxv-b2g87", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:YANol02", "type": "article", "title": "Photorefractive recording in LiNbO3:Mn", "author": [ { "family_name": "Yang", "given_name": "Yunping", "clpid": "Yang-Y" }, { "family_name": "Buse", "given_name": "Karsten", "clpid": "Buse-K" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "The dynamic range, sensitivity, and dark decay of holographic recording of wavelength 458nm in LiNbO3 crystals doped with 0.2-at.% Mn with different oxidation states have been measured. The measured sensitivity is 0.5 cm/J and is found to be independent of the oxidation state, and the largest M/# obtained is 12/mm (extraordinary light polarization; light wavelength, 458nm). This combination of very large M/# and high sensitivity is in strong contrast with results for LiNbO3:Fe for which a direct trade-off exists between M/# and sensitivity. The activation energy of the dark decay of holograms stored in these LiNbO3:Mn crystals is 1.0 eV , which is characteristic of proton compensation and leads to a projected lifetime of holograms of three years at room temperature.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "2002-02-01", "series_number": "3", "volume": "27", "issue": "3", "pages": "158-160" }, { "id": "authors:f54h2-yg803", "collection": "authors", "collection_id": "f54h2-yg803", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LIUol02b", "type": "article", "title": "Holographic recording of fast events on a CCD camera", "author": [ { "family_name": "Liu", "given_name": "Zhiwen", "clpid": "Liu-Zhiwen" }, { "family_name": "Centurion", "given_name": "Martin", "clpid": "Centurion-M" }, { "family_name": "Panotopoulos", "given_name": "George", "clpid": "Panotopoulos-G" }, { "family_name": "Hong", "given_name": "John", "clpid": "Hong-J" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We report on holographic recording of nanosecond events on a conventional CCD camera. Three frames of an air-discharge event, with resolution of 5.9 ns and frame interval of 12 ns, are recorded in a single CCD frame. Each individual frame is reconstructed by digital filtering of the CCD frame, since successively recorded holograms are centered at different carrier frequencies in the spatial frequency domain.", "doi": "10.1364/OL.27.000022", "issn": "0146-9592", "publisher": "Optical Society of America", "publication": "Optics Letters", "publication_date": "2002-01-01", "series_number": "1", "volume": "27", "issue": "1", "pages": "22-24" }, { "id": "authors:224vs-bz946", "collection": "authors", "collection_id": "224vs-bz946", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ADIao01", "type": "article", "title": "System Measure for Persistence in Holographic Recording and Application to Singly-Doped and Doubly-Doped Lithium Niobate", "author": [ { "family_name": "Adibi", "given_name": "Ali", "clpid": "Adibi-A" }, { "family_name": "Buse", "given_name": "Karsten", "clpid": "Buse-K" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We define a measure for persistence in holographic recording. Using this measure and the known measures for dynamic range and sensitivity, we compare the performance of singly-doped and doubly-doped LiNbO3 crystals. We show that the range of performance that can be obtained using doubly-doped crystals is much larger than that obtained using singly-doped ones.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "2001-10-10", "series_number": "29", "volume": "40", "issue": "29", "pages": "5175-5182" }, { "id": "authors:7dbrv-22976", "collection": "authors", "collection_id": "7dbrv-22976", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:MOSao01", "type": "article", "title": "Holographic memory with localized recording", "author": [ { "family_name": "Moser", "given_name": "Christophe", "clpid": "Moser-C" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We experimentally demonstrate and characterize a memory module that features selective page erasure and readout persistence using the localized recording method in doubly doped LiNbO3. Pages of information can be selectively erased without partially erasing the whole memory. Data pages can be written over erased pages multiple times. Information is read millions of times before refreshing is required. We quantify the optical quality of the holograms by measuring their signal-to-noise ratio for a memory size up to 100 holograms. A compact phase-conjugate readout architecture is also presented and experimentally demonstrated.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "2001-08-10", "series_number": "23", "volume": "40", "issue": "23", "pages": "3909-3914" }, { "id": "authors:5d8pd-kzh15", "collection": "authors", "collection_id": "5d8pd-kzh15", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:STEao01", "type": "article", "title": "Storage Density of Shift-Multiplexed Holographic Memory", "author": [ { "family_name": "Steckman", "given_name": "Gregory J.", "clpid": "Steckman-G-F" }, { "family_name": "Pu", "given_name": "Allen", "clpid": "Pu-A" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "The storage density of shift-multiplexed holographic memory is calculated and compared with experimentally achieved densities by use of photorefractive and write-once materials. We consider holographic selectivity as well as the recording material s dynamic range (M /#) and required diffraction efficiencies in formulating the calculations of storage densities, thereby taking into account all major factors limiting the raw storage density achievable with shift-multiplexed holographic storage systems. We show that the M /# is the key factor in limiting storage densities rather than the recording material s thickness for organic materials in which the scatter is relatively high. A storage density of 100 bits m2 is experimentally demonstrated by use of a 1-mm-thick LiNbO3 crystal as the recording medium.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "2001-07-10", "series_number": "20", "volume": "40", "issue": "20", "pages": "3387-3394" }, { "id": "authors:tq6em-ff038", "collection": "authors", "collection_id": "tq6em-ff038", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:YANapl01", "type": "article", "title": "Ionic and electronic dark decay of holograms in LiNbO3:Fe crystals", "author": [ { "family_name": "Yang", "given_name": "Yunping", "clpid": "Yang-Y" }, { "family_name": "Nee", "given_name": "Ingo", "clpid": "Nee-I" }, { "family_name": "Buse", "given_name": "Karsten", "clpid": "Buse-K" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "The lifetimes of nonfixed holograms in LiNbO3:Fe crystals with doping levels of 0.05, 0.138, and 0.25 wt % Fe2O3 have been measured in the temperature range from 30 to 180 \u00b0C. The time constants of the dark decay of holograms stored in crystals with doping levels of 0.05 and 0.25 wt % Fe2O3 obey an Arrhenius-type dependence on absolute temperature T, but yield two activation energies: 1.0 and 0.28 eV, respectively. For these crystals, two different dark decay mechanisms are prevailing, one of which is identified as proton compensation and the other is due to electron tunneling between sites of Fe2 + and Fe3 + . The dark decay of holograms stored in crystals with the doping level of 0.138 wt % Fe2O3 is the result of a combination of both effects.", "doi": "10.1063/1.1380247", "issn": "0003-6951", "publisher": "Applied Physics Letters", "publication": "Applied Physics Letters", "publication_date": "2001-06-25", "series_number": "26", "volume": "78", "issue": "26", "pages": "4076-4078" }, { "id": "authors:sszcb-rva68", "collection": "authors", "collection_id": "sszcb-rva68", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ADIjosab01", "type": "article", "title": "Two-center holographic recording", "author": [ { "family_name": "Adibi", "given_name": "Ali", "clpid": "Adibi-A" }, { "family_name": "Buse", "given_name": "Karsten", "clpid": "Buse-K" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We describe a two-center holographic recording method for the storage of persistent holograms in doubly doped lithium niobate crystals. We use a two-center model, and we show that our experimental observations can be explained by the model. We describe experimental methods for finding the unknown material parameters of LiNbO3:Fe:Mn crystals for the two-center model, and we discuss the optimization of two-center recording.", "issn": "0740-3224", "publisher": "Optical Society of America", "publication": "Journal of the Optical Society of America B", "publication_date": "2001-05", "series_number": "5", "volume": "18", "issue": "5", "pages": "584-601" }, { "id": "authors:wytrf-0vs90", "collection": "authors", "collection_id": "wytrf-0vs90", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170408-140528298", "type": "article", "title": "The role of carrier mobility in holographic recording in LiNbO_3", "author": [ { "family_name": "Adibi", "given_name": "A.", "clpid": "Adibi-A" }, { "family_name": "Buse", "given_name": "K.", "clpid": "Buse-K" }, { "family_name": "Psaltis", "given_name": "D.", "clpid": "Psaltis-D" } ], "doi": "10.1007/s003400100593", "issn": "1432-0649", "publisher": "Applied Physics B", "publication": "Applied Physics B", "publication_date": "2001-05", "series_number": "6", "volume": "72", "issue": "6", "pages": "653-659" }, { "id": "authors:b5xzz-ge521", "collection": "authors", "collection_id": "b5xzz-ge521", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:WANjosaa01", "type": "article", "title": "Measuring and modeling optical diffraction from\n subwavelength features", "author": [ { "family_name": "Wang", "given_name": "Xu", "clpid": "Wang-Xu" }, { "family_name": "Mason", "given_name": "Jeffrey", "clpid": "Mason-J" }, { "family_name": "Latta", "given_name": "Milton", "clpid": "Latta-M" }, { "family_name": "Strand", "given_name": "Timothy C.", "clpid": "Strand-T-C" }, { "family_name": "Marx", "given_name": "David", "clpid": "Marx-D" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We describe a technique for studying scattering from subwavelength features. A simple scatterometer was developed to measure the scattering from the single-submicrometer, subwavelength features generated with a focused ion beam system. A model that can describe diffraction from subwavelength features with arbitrary profiles is also presented and shown to agree quite well with the experimental measurements. The model is used to demonstrate ways in which the aspect ratios of subwavelength ridges and trenches can be obtained from scattering data and how ridges can be distinguished from trenches over a wide range of aspect ratios. We show that some earlier results of studies on distinguishing pits from particles do not extend to low-aspect-ratio features.", "issn": "1084-7529", "publisher": "Optical Society of America", "publication": "Journal of the Optical Society of America A", "publication_date": "2001-03", "series_number": "3", "volume": "18", "issue": "3", "pages": "565-572" }, { "id": "authors:fjbsj-se698", "collection": "authors", "collection_id": "fjbsj-se698", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ADIpra01", "type": "article", "title": "Theoretical analysis of two-step holographic recording with high-intensity pulses", "author": [ { "family_name": "Adibi", "given_name": "Ali", "clpid": "Adibi-A" }, { "family_name": "Buse", "given_name": "Karsten", "clpid": "Buse-K" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We develop a full numerical as well as an approximate analytic solution for two-step holographic recording with high intensity pulses in LiNbO3:Fe crystals. We find the unknown material parameters by fitting the numerical solution to the experimental results. The two important parameters that were unknown so far and found in this work are the bulk photovoltaic coefficient and absorption cross section for the excitation of the electrons from small polarons in LiNbO3 with infrared light. We show that the approximate analytic solution agrees very well with the numerical solution (as well as the experimental results) for most practical applications. We use the analytic solution to explain the experimental observations that were not understood before.", "doi": "10.1103/PhysRevA.63.023813", "issn": "1050-2947", "publisher": "Physical Review A", "publication": "Physical Review A", "publication_date": "2001-02-01", "series_number": "2", "volume": "63", "issue": "2", "pages": "Art. no. 023813" }, { "id": "authors:pepw4-nk167", "collection": "authors", "collection_id": "pepw4-nk167", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111129-150503089", "type": "article", "title": "Liquid-Crystal Blazed-Grating Beam Deflector", "author": [ { "family_name": "Wang", "given_name": "Xu", "clpid": "Wang-Xu" }, { "family_name": "Wilson", "given_name": "Daniel", "clpid": "Wilson-Daniel" }, { "family_name": "Muller", "given_name": "Richard", "clpid": "Muller-R" }, { "family_name": "Maker", "given_name": "Paul", "clpid": "Maker-P" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "A transmission-type nonmechanical multiple-angle beam-steering device that uses liquid-crystal blazed grating has been developed. Sixteen steering angles with a contrast ratio of 18 has been demonstrated. A detailed analysis of the liquid-crystal and poly(methyl methacrylate) blazed-grating deflector was carried out to provide guidance during the deflector's development. A manufacturing offset compensation technique is proposed to improve the device's performance greatly. A hybrid approach utilizing electrically generated blazed grating combined with the cascading approach described here yields in excess of 500 deflecting angles.", "doi": "10.1364/AO.39.006545", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "2000-12-10", "series_number": "35", "volume": "39", "issue": "35", "pages": "6545-6555" }, { "id": "authors:an655-c0d74", "collection": "authors", "collection_id": "an655-c0d74", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:MOSol00a", "type": "article", "title": "Diffraction efficiency of localized holograms in doubly doped LiNbO3 crystals", "author": [ { "family_name": "Moser", "given_name": "Christophe", "clpid": "Moser-C" }, { "family_name": "Maravic", "given_name": "Irena", "clpid": "Maravic-I" }, { "family_name": "Schupp", "given_name": "Benjamin", "clpid": "Schupp-B" }, { "family_name": "Adibi", "given_name": "Ali", "clpid": "Adibi-A" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "The diffraction efficiency of M holograms superimposed in the volume of the recording medium is proportional to 1/M^2. We present a method, based on nondestructive localized holograms in a doubly doped LiNbO3 crystal, that allows us to also record M holograms in the same volume without an exposure schedule or a diffraction efficiency that has 1/M dependence. We compare experimentally the final diffraction efficiency obtained with the localized and distributed recording methods.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "2000-09-01", "series_number": "17", "volume": "25", "issue": "17", "pages": "1243-1245" }, { "id": "authors:11xd4-1na17", "collection": "authors", "collection_id": "11xd4-1na17", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:STEol00", "type": "article", "title": "Holographic recording in a photopolymer by optically induced detachment of chromophores", "author": [ { "family_name": "Steckman", "given_name": "Gregory J.", "clpid": "Steckman-G-J" }, { "family_name": "Shelkovnikov", "given_name": "Vladimir", "clpid": "Shelkovnikov-V" }, { "family_name": "Berezhnaya", "given_name": "Victoria", "clpid": "Berezhnaya-V" }, { "family_name": "Gerasimova", "given_name": "Tatiana", "clpid": "Gerasimova-T" }, { "family_name": "Solomatine", "given_name": "Iouri", "clpid": "Solomatine-I" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We demonstrate holographic recording in a new photopolymer system. The recording material is created by copolymerization of an optically inert monomer, methyl methacrylate, and a second monomer that is optically sensitive. On exposure of the recording material to light, a portion of the optically sensitive component detaches from the polymer matrix and causes hologram amplification through diffusion of the free molecules. We measured postrecording grating amplifications as high as 170% by this process. The recorded holograms are persistent at room temperature under continuous illumination at the recording wavelength.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "2000-05-01", "series_number": "9", "volume": "25", "issue": "9", "pages": "607-609" }, { "id": "authors:g9jnk-gfp79", "collection": "authors", "collection_id": "g9jnk-gfp79", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:YUEjap00", "type": "article", "title": "Role of cerium in lithium niobate for holographic recording", "author": [ { "family_name": "Yue", "given_name": "Xuefeng", "clpid": "Yue-X" }, { "family_name": "Adibi", "given_name": "A.", "clpid": "Adibi-A" }, { "family_name": "Hudson", "given_name": "T.", "clpid": "Hudson-T" }, { "family_name": "Buse", "given_name": "K.", "clpid": "Buse-K" }, { "family_name": "Psaltis", "given_name": "D.", "clpid": "Psaltis-D" } ], "abstract": "Cerium-doped lithium niobate crystals are tested for holographic recording. A photochromic effect is observed in crystals doped with cerium and manganese. But two-center recording in the sample is not as effective as in iron and manganese doubly doped crystals. Photocurrent measurements in cerium and iron singly doped crystals indicate that the photovoltaic constant in the cerium-doped crystal is only one third of that of the iron-doped one. This is the main reason accounting for the low sensitivity of cerium-doped lithium niobate crystals. However, in the diffusion dominated case, i.e., for reflection geometry, cerium-doped lithium niobate may give a strong effect.", "doi": "10.1063/1.373043", "issn": "0021-8979", "publisher": "Journal of Applied Physics", "publication": "Journal of Applied Physics", "publication_date": "2000-05-01", "series_number": "9", "volume": "87", "issue": "9", "pages": "4051-4055" }, { "id": "authors:4ehzn-neh60", "collection": "authors", "collection_id": "4ehzn-neh60", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ADIol00", "type": "article", "title": "Sensitivity improvement in two-center holographic recording", "author": [ { "family_name": "Adibi", "given_name": "Ali", "clpid": "Adibi-A" }, { "family_name": "Buse", "given_name": "Karsten", "clpid": "Buse-K" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "Persistent holograms are recorded with green light in LiNbO3 crystals doped with Mn and Fe. The recording sensitivity is 20 times better than that obtained by recording with red light. Partial loss of persistence is caused by using green light for recording.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "2000-04-15", "series_number": "8", "volume": "25", "issue": "8", "pages": "539-541" }, { "id": "authors:h2zvn-w5s84", "collection": "authors", "collection_id": "h2zvn-w5s84", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:MOSol00b", "type": "article", "title": "Localized holographic recording in doubly doped lithium niobate", "author": [ { "family_name": "Moser", "given_name": "Christophe", "clpid": "Moser-C" }, { "family_name": "Schupp", "given_name": "Benjamin", "clpid": "Schupp-B" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "Persistent holograms are recorded locally with red light in a LiNbO>3 crystal doped with Mg and Fe. Selective erasure is realized by use of a focused UV sensitizing light. We demonstrate the recording of 50 localized images as well as selective erasure in a 4 mm \u00d7 4 mm \u00d7 4 mm crystal. A comparison of the total recording time for M holograms obtained with the conventional distributed-volume recording and the localized methods is presented.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "2000-02-01", "series_number": "3", "volume": "25", "issue": "3", "pages": "162-164" }, { "id": "authors:sz32v-5pc22", "collection": "authors", "collection_id": "sz32v-5pc22", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LIUol99", "type": "article", "title": "Pixel size limit in holographic memories", "author": [ { "family_name": "Liu", "given_name": "Wenhai", "clpid": "Liu-Wenhai" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "The bandwidth of holographic recording in LiNbO3 (Fe doped) in the 90\u00b0 geometry is studied theoretically and experimentally. The wide holographic bandwidth of LiNbO3 makes it possible to record submicrometer pixels and reconstruct them by phase conjugation in a holographic memory system. This approach reduces the system cost and increases the system storage density. We demonstrate the recording and the phase-conjugate reconstruction of various pixel sizes down to 1 \u03bcm \u00d7 1 \u03bcm . The signal\u2013noise ratio and the bit-error rate are examined.", "doi": "10.1364/OL.24.001340", "issn": "0146-9592", "publisher": "Optical Society of America", "publication": "Optics Letters", "publication_date": "1999-10-01", "series_number": "19", "volume": "24", "issue": "19", "pages": "1340-1342" }, { "id": "authors:tztf0-t3a33", "collection": "authors", "collection_id": "tztf0-t3a33", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ADIao99", "type": "article", "title": "Secondary Grating Formation by Readout at Bragg-null Incidence", "author": [ { "family_name": "Adibi", "given_name": "Ali", "clpid": "Adibi-A" }, { "family_name": "Mumbru", "given_name": "Jose", "clpid": "Mumbru-J" }, { "family_name": "Wagner", "given_name": "Kelvin", "clpid": "Wagner-K-H" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We show that when a dynamic hologram is read out by illumination at the Bragg nulls of a previously recorded grating the diffracted beam inside the medium can result in the recording of two secondary gratings that alter the final selectivity curve. This is confirmed experimentally. This effect can cause cross talk in hologram multiplexing that is stronger than interpage cross talk when a small number of\nholograms with high diffraction efficiencies are multiplexed.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1999-07-10", "series_number": "20", "volume": "38", "issue": "20", "pages": "4291-4295" }, { "id": "authors:jctsp-5c667", "collection": "authors", "collection_id": "jctsp-5c667", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ADIol99", "type": "article", "title": "Multiplexing holograms in LiNbO3FeMn crystals", "author": [ { "family_name": "Adibi", "given_name": "Ali", "clpid": "Adibi-A" }, { "family_name": "Buse", "given_name": "Karsten", "clpid": "Buse-K" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "Persistent holograms are recorded with red light in lithium niobate crystals doped with manganese and iron. Different erasure mechanisms are investigated, and a recording schedule for multiplexing holograms with equal diffraction efficiencies is proposed. To test the recording schedule experimentally, we multiplex 50 plane-wave holograms with the proposed recording schedule.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "1999-05-15", "series_number": "10", "volume": "24", "issue": "10", "pages": "652-654" }, { "id": "authors:0n3z3-xjn76", "collection": "authors", "collection_id": "0n3z3-xjn76", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BUSjoa99", "type": "article", "title": "Efficient non-volatile holographic recording in doubly doped lithium niobate", "author": [ { "family_name": "Buse", "given_name": "Karsten", "clpid": "Buse-K" }, { "family_name": "Adibi", "given_name": "Ali", "clpid": "Adibi-A" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We present an efficient, non-volatile holographic storage scheme in doubly doped lithium niobate, with red recording light and simultaneous illumination by homogeneous ultraviolet light.", "doi": "10.1088/1464-4258/1/2/023", "issn": "1464-4258", "publisher": "Journal of Optics A: Pure and Applied Optics", "publication": "Journal of Optics A: Pure and Applied Optics", "publication_date": "1999-03-01", "series_number": "2", "volume": "1", "issue": "2", "pages": "237-238" }, { "id": "authors:7sbbk-48727", "collection": "authors", "collection_id": "7sbbk-48727", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ANXao99", "type": "article", "title": "Thermal Fixing of 10,000 Holograms in LiNbO3:Fe", "author": [ { "family_name": "An", "given_name": "Xin", "clpid": "An-Xin" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Burr", "given_name": "Geoffrey W.", "clpid": "Burr-G-W" } ], "abstract": "We discuss thermal fixing as a solution to the volatility problem in holographic storage systems that use photorefractive materials such as LiNbO3:Fe. We present a systematic study to characterize the effect of thermal fixing on the error performance of a large-scale holographic memory. We introduce a novel, to our knowledge, incremental fixing schedule to improve the overall system fixing efficiency. We thermally fixed 10,000 holograms in a 90 degree-geometry setup by using this new schedule. All the fixed holograms were retrieved with no errors.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1999-01-10", "series_number": "2", "volume": "38", "issue": "2", "pages": "386-393" }, { "id": "authors:dgv5s-7y328", "collection": "authors", "collection_id": "dgv5s-7y328", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LEVao99", "type": "article", "title": "Method for controlling the shift invariance of optical correlators", "author": [ { "family_name": "Levene", "given_name": "Michael", "clpid": "Levene-M" }, { "family_name": "Steckman", "given_name": "Gregory J.", "clpid": "Steckman-G-J" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "Holographic correlators can implement many correlations in parallel. For most systems shift invariance limits the number of correlation templates that can be stored in one correlator. This is because the output plane must be divided among the individual templates in the system. When the system is completely shift invariant, the correlation peak from one correlator can shift into an area that has been reserved for a different template; in this case a shifted version of one object might be mistaken for a well-centered version of a different object. We describe a technique for controlling the shift invariance of a correlator system by moving the holographic material away from the Fourier plane.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1999-01-10", "series_number": "2", "volume": "38", "issue": "2", "pages": "394-398" }, { "id": "authors:g5cge-nxb78", "collection": "authors", "collection_id": "g5cge-nxb78", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:STEol98a", "type": "article", "title": "Characterization of phenanthrenequinone-doped poly(methyl methacrylate) for holographic memory", "author": [ { "family_name": "Steckman", "given_name": "Gregory J.", "clpid": "Steckman-G-J" }, { "family_name": "Solomatine", "given_name": "Iouri", "clpid": "Solomatine-I" }, { "family_name": "Zhou", "given_name": "Gan", "clpid": "Zhou-G" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "The holographic recording characteristics of phenanthrenequinone- (PQ-) doped poly(methyl methacrylate) are investigated. The exposure sensitivity is characterized for single-hologram recording, and the M/# is measured for samples as thick as 3 mm. Optically induced birefringence is observed in this material.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "1998-08-15", "series_number": "16", "volume": "23", "issue": "16", "pages": "1310-1312" }, { "id": "authors:znhvq-59942", "collection": "authors", "collection_id": "znhvq-59942", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230412-848441000.2", "type": "article", "title": "Non-volatile holographic storage in doubly doped lithium niobate crystals", "author": [ { "family_name": "Buse", "given_name": "K.", "orcid": "0000-0002-7590-8131", "clpid": "Buse-Karsten" }, { "family_name": "Adibi", "given_name": "A.", "orcid": "0000-0003-0302-0907", "clpid": "Adibi-Ali" }, { "family_name": "Psaltis", "given_name": "D.", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" } ], "abstract": "Photorefractive materials are being widely investigated for applications in holographic data storage. Inhomogeneous illumination of these materials with an optical interference pattern redistributes charge, builds up internal electric fields and so changes the refractive index. Subsequent homogeneous illumination results in light diffraction and reconstructs the information encoded in the original interference pattern. A range of inorganic and organic photorefractive materials are known, in which thousands of holograms of high fidelity can be efficiently stored, reconstructed and erased. But there remains a problem with volatility: the read-out process usually erases the stored information and amplifies the scattered light. Several techniques for 'fixing' holograms have been developed, but they have practical disadvantages and only laboratory demonstrators have been built. Here we describe a resolution to the problem of volatility that should lead to the realization of a more practical system. We use crystals of lithium niobate \u2014 available both in large size and with excellent homogeneity \u2014 that have been doped with two different deep electron traps (iron and manganese). Illumination of the crystals with incoherent ultraviolet light during the recording process permits the storage of data (a red-light interference pattern) that can be subsequently read, in the absence of ultraviolet light, without erasure. Our crystals show up to 32 per cent diffraction efficiency, rapid optical erasure of the stored data is possible using ultraviolet light, and light scattering is effectively prevented.", "doi": "10.1038/31429", "issn": "0028-0836", "publisher": "Nature Publishing Group", "publication": "Nature", "publication_date": "1998-06", "series_number": "6686", "volume": "393", "issue": "6686", "pages": "665-668" }, { "id": "authors:w831c-pjh94", "collection": "authors", "collection_id": "w831c-pjh94", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CHUao97", "type": "article", "title": "Storage of 1000 holograms with use of a dual-wavelength method", "author": [ { "family_name": "Chuang", "given_name": "Ernest", "clpid": "Chuang-E" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We demonstrate the storage of 1000 holograms in a memory architecture that makes use of different wavelengths for recording and readout to reduce the grating decay while retrieving data. Bragg-mismatch problems from the use of two wavelengths are minimized through recording in the image plane and using thin crystals. Peristrophic multiplexing can be combined with angle multiplexing to counter the poorer angular selectivity of thin crystals. Dark conductivity reduces the effectiveness of the dual-wavelength method for nonvolatile readout, and constraints on the usable pixel sizes limit this method to moderate storage densities.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1997-11-10", "series_number": "32", "volume": "36", "issue": "32", "pages": "8445-8454" }, { "id": "authors:75yvd-yzj03", "collection": "authors", "collection_id": "75yvd-yzj03", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170809-111634119", "type": "article", "title": "Real-time vehicle navigation using a holographic memory", "author": [ { "family_name": "Pu", "given_name": "Allen", "clpid": "Pu-Allen" }, { "family_name": "Denkewalter", "given_name": "Robert", "clpid": "Denkewalter-R" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We describe an optoelectronic information processing system that is capable of real-time vehicle navigation and target acquisition. The system uses a holographic database, based on the DuPont HRF-150 photopolymer, to perform the desired tasks. The architecture and the performance of the system are discussed in detail.", "doi": "10.1117/1.601467", "issn": "0091-3286", "publisher": "Society of Photo-Optical Instrumentation Engineers", "publication": "Optical Engineering", "publication_date": "1997-10", "series_number": "10", "volume": "36", "issue": "10", "pages": "2737-2746" }, { "id": "authors:jzdch-jy561", "collection": "authors", "collection_id": "jzdch-jy561", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120130-072241378", "type": "article", "title": "Polarization quadrature measurement of subwavelength diffracting structures", "author": [ { "family_name": "Marx", "given_name": "D. S.", "clpid": "Marx-D-S" }, { "family_name": "Psaltis", "given_name": "D.", "clpid": "Psaltis-D" } ], "abstract": "The amplitude and the phase of the diffracted far field depends on polarization when the diffracting structure is comparable to or less than the wavelength. When the far-field amplitude and the phase of one polarization with respect to the orthogonal polarization is measured, small changes in the structure can be measured. To make the far-field polarization measurements, we design a detector that measures the relative polarization amplitude and the phase in quadrature. We predict numerically and verify experimentally the polarization amplitude and the phase for an optical disc and a set of gratings with varying depth. Our results show that this measurement technique is sensitive to small variations in the diffracting structure and that it can be useful in applications such as critical dimension and overlay metrology in microelectronics fabrication.", "doi": "10.1364/AO.36.006434", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1997-09-01", "series_number": "25", "volume": "36", "issue": "25", "pages": "6434-6440" }, { "id": "authors:vywc5-5yx90", "collection": "authors", "collection_id": "vywc5-5yx90", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:REDol97", "type": "article", "title": "Holographic data storage in a DX-center material", "author": [ { "family_name": "Redmond", "given_name": "I. R.", "clpid": "Redmond-I-R" }, { "family_name": "Linke", "given_name": "R. A.", "clpid": "Linke-R-A" }, { "family_name": "Chuang", "given_name": "E.", "clpid": "Chuang-E" }, { "family_name": "Psaltis", "given_name": "D.", "clpid": "Psaltis-D" } ], "abstract": "We report on the optical storage of digital data in a semiconductor sample containing DX centers. The diffraction efficiency and the bit-error-rate performance of multiplexed data images are shown to agree well with a simple model of the material. Uniform storage without an exposure schedule is demonstrated. The volume sensitivity is found to be ~10^3 times that of LiNBO3:Fe. The importance of coherent addition of scattered light with diffracted light in holographic data storage is discussed.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "1997-08-01", "series_number": "15", "volume": "22", "issue": "15", "pages": "1189-1191" }, { "id": "authors:dz2bp-7dq83", "collection": "authors", "collection_id": "dz2bp-7dq83", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:MAJol97", "type": "article", "title": "Electrical fixing of 1000 angle-multiplexed holograms in SBN:75", "author": [ { "family_name": "Ma", "given_name": "Jian", "clpid": "Ma-J" }, { "family_name": "Chang", "given_name": "Tallis", "clpid": "Chang-T" }, { "family_name": "Hong", "given_name": "John", "clpid": "Hong-J" }, { "family_name": "Neurgaonkar", "given_name": "Ratnakar", "clpid": "Neurgaonkar-R-R" }, { "family_name": "Barbastathis", "given_name": "George", "clpid": "Barbastathis-G" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We have demonstrated electrical fixing of 1000 angle-multiplexed holograms in a 1-cm^3 volume Ce-doped SBN:75 crystal. A revealing procedure yielded an average diffraction efficiency of 0.005% for each hologram, with approximately 20% variation. The erasure resistance of the fixed gratings was verified.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "1997-07-15", "series_number": "14", "volume": "22", "issue": "14", "pages": "1116-1118" }, { "id": "authors:4ghad-xbk55", "collection": "authors", "collection_id": "4ghad-xbk55", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:DROol97", "type": "article", "title": "Compact, integrated dynamic holographic memory with refreshed holograms", "author": [ { "family_name": "Drolet", "given_name": "Jean-Jacques P.", "clpid": "Drolet-J-J-P" }, { "family_name": "Chuang", "given_name": "Ernest", "clpid": "Chuang-E" }, { "family_name": "Barbastathis", "given_name": "George", "clpid": "Barbastathis-G" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "An innovative architecture for compact, integrated volume holographic memories is described. It is based on phase-conjugate readout and on a modulator\u2013detector\u2013memory array implemented in a silicon integrated circuit. The lensless memory module sustains dynamic read\u2013write holograms by periodic refreshing. The integrated circuit is described and experimentally characterized. Holograms were stored in a prototype storage module that uses a 30 degree-cut BaTiO3 crystal and the 90\u00b1 recording geometry. As many as three angularly multiplexed holograms were periodically refreshed and subjected to .40% decay from exposure to the reference beam over 50 to 100 cycles. Experimental data are presented.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "1997-04-15", "series_number": "8", "volume": "22", "issue": "8", "pages": "552-554" }, { "id": "authors:wr4nk-m8y70", "collection": "authors", "collection_id": "wr4nk-m8y70", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161005-152423097", "type": "article", "title": "Exposure schedule for multiplexing holograms in photopolymer films", "author": [ { "family_name": "Pu", "given_name": "Allen", "clpid": "Pu-A" }, { "family_name": "Curtis", "given_name": "Kevin", "clpid": "Curtis-K" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "An iterative method is introduced for determining the exposure schedule for multiplexing holograms in saturable recording materials, such as photopolymers. This method is designed to share all or part of the available dynamic range of the recording material among the holograms to be multiplexed. Using exposure schedules derived from this method, the authors find that the diffraction efficiency of DuPont's HRF\u2010150 38\u2010 and 100\u2010\u03bcm photopolymer scale is (2.2/M)^2 and (6.5/M)^2 respectively, where M is the number of holograms recorded. Finally, 1000 holograms were multiplexed at a single location in the 100\u2010\u03bcm thick photopolymer using an exposure schedule derived with this method.", "doi": "10.1117/1.600967", "issn": "0091-3286", "publisher": "Society of Photo-Optical Instrumentation Engineers", "publication": "Optical Engineering", "publication_date": "1996-10", "series_number": "10", "volume": "35", "issue": "10", "pages": "2824-2829" }, { "id": "authors:85226-m6q65", "collection": "authors", "collection_id": "85226-m6q65", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BURol96", "type": "article", "title": "Effect of the oxidation state of LiNbO3:Fe on the diffraction efficiency of multiple holograms", "author": [ { "family_name": "Burr", "given_name": "Geoffrey W.", "clpid": "Burr-G-W" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We show that the oxidation state of Fe in LiNbO3 has two competing effects on the diffraction efficiency of multiple holograms in 90 degree-geometry holographic storage. For crystals with moderate absorption, the saturation space-charge field is larger after high-temperature reduction treatment. However, reduction also increases absorption, which reduces the overall diffraction efficiency. We develop a theoretical model that predicts achievable diffraction efficiency as a function of oxidation state, doping level, photovoltaic field, crystal length, and region of beam overlap. We compare this model with experimental results for achievable diffraction efficiency and erasure-time constant.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "1996-06-15", "series_number": "12", "volume": "21", "issue": "12", "pages": "893-895" }, { "id": "authors:rx8az-emr54", "collection": "authors", "collection_id": "rx8az-emr54", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:MOKol96", "type": "article", "title": "System metric for holographic memory systems", "author": [ { "family_name": "Mok", "given_name": "Fai H.", "clpid": "Mok-F-H" }, { "family_name": "Burr", "given_name": "Geoffrey W.", "clpid": "Burr-G-W" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We introduce M/# as a metric for characterizing holographic memory systems. M/# is the constant of proportionality between diffraction efficiency and the number of holograms squared. Although M/# is a function of many variables in a holographic recording system, it can be measured from the recording and erasure of a single hologram. We verify experimentally that the diffraction efficiency of multiple holograms follows the prediction of M/# measured from a single hologram.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "1996-06-15", "series_number": "12", "volume": "21", "issue": "12", "pages": "896-898" }, { "id": "authors:9knh1-5a013", "collection": "authors", "collection_id": "9knh1-5a013", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BARao96", "type": "article", "title": "Shift multiplexing with spherical reference waves", "author": [ { "family_name": "Barbastathis", "given_name": "George", "clpid": "Barbastathis-G" }, { "family_name": "Levene", "given_name": "Michael", "clpid": "Levene-M" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "Shift multiplexing is a holographic storage method particularly suitable for the implementation of holographic disks. We characterize the performance of shift-multiplexed memories by using a spherical wave as the reference beam. We derive the shift selectivity, the cross talk, the exposure schedule, and the storage density of the method. We give experimental results to verify the theoretical predictions.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1996-05-10", "series_number": "14", "volume": "35", "issue": "14", "pages": "2408-2422" }, { "id": "authors:25gx8-2ef96", "collection": "authors", "collection_id": "25gx8-2ef96", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:PUAao96", "type": "article", "title": "High-density recording in photopolymer-based holographic three-dimensional disks", "author": [ { "family_name": "Pu", "given_name": "Allen", "clpid": "Pu-A" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "The performance specifications of a holographic three-dimensional disk system are experimentally characterized. A surface density of 10 bits/\u03bcm^2 is experimentally demonstrated with a 100-\u03bcm-thick photopolymer as the recording medium.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1996-05-10", "series_number": "14", "volume": "35", "issue": "14", "pages": "2389-2398" }, { "id": "authors:eqv6d-71r65", "collection": "authors", "collection_id": "eqv6d-71r65", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:NEIao96", "type": "article", "title": "Optical memory: introduction by the feature editors", "author": [ { "family_name": "Neifeld", "given_name": "Mark A.", "clpid": "Neifeld-M-A" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Hesselink", "given_name": "Lambertos", "clpid": "Hesselink-L" } ], "abstract": "The contributions to this feature issue represent a wide range of topics in optical memory.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1996-05-10", "series_number": "14", "volume": "35", "issue": "14", "pages": "2345" }, { "id": "authors:hekjd-k8q21", "collection": "authors", "collection_id": "hekjd-k8q21", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BARol96", "type": "article", "title": "Shift-multiplexed holographic memory using the two-lambda method", "author": [ { "family_name": "Barbastathis", "given_name": "George", "clpid": "Barbastathis-G" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We present theoretical and experimental results on the application of the two-lambda method for prolonged readout of holographic memories to shift multiplexing implemented with a spherical-wave reference beam.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "1996-03-15", "series_number": "6", "volume": "21", "issue": "6", "pages": "432-434" }, { "id": "authors:xra7s-0fx85", "collection": "authors", "collection_id": "xra7s-0fx85", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ANDol95", "type": "article", "title": "Optical-radar imaging of scale models for studies in asteroid astronomy", "author": [ { "family_name": "Andrews", "given_name": "A. K.", "clpid": "Andrews-A-K" }, { "family_name": "Hudson", "given_name": "R. S.", "clpid": "Hudson-R-S" }, { "family_name": "Psaltis", "given_name": "D.", "clpid": "Psaltis-D" } ], "abstract": "During the past five years, delay-Doppler radar has become the primary technique for studying the structure of Earth-crossing asteroids. None of these objects has yet been visited by spacecraft, so ground-truth test cases are lacking. A laboratory system is described that provides optical-radar images at 0.1-mm resolution. These data are analogous to the highest-resolution asteroid radar images currently available and provided realistic test cases for developing signal-processing techniques. The system can be thought of as a 1/188,000 scale model of the Arecibo radar, or a 1/52,800 scale model of the Goldstone radar.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "1995-11-15", "series_number": "22", "volume": "20", "issue": "22", "pages": "2327-2329" }, { "id": "authors:p4dzy-67p52", "collection": "authors", "collection_id": "p4dzy-67p52", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:DROol95", "type": "article", "title": "Hybrid-aligned nematic liquid-crystal modulators fabricated on VLSI circuits", "author": [ { "family_name": "Drolet", "given_name": "Jean-Jacques P.", "clpid": "Drolet-J-J-P" }, { "family_name": "Patel", "given_name": "Jay S.", "clpid": "Patel-Jay-S" }, { "family_name": "Haritos", "given_name": "Konstantinos G.", "clpid": "Haritos-Konstantinos-G" }, { "family_name": "Xu", "given_name": "Weihua", "clpid": "Xu-Weihua" }, { "family_name": "Scherer", "given_name": "Axel", "orcid": "0000-0002-2160-9064", "clpid": "Scherer-A" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "A new method for fabricating analog light modulators on VLSI devices is described. The process is fully compatible with devices fabricated by commercial VLSI foundries, and the assembly of the modulator structures requires a small number of simple processing steps. The modulators are capable of analog amplitude or phase modulation and can operate at video rates and at low voltages (2.2 V). The modulation mechanism and the process yielding the modulator structures are described. Experimental data are presented.", "doi": "10.1364/OL.20.002222", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "1995-11-01", "series_number": "21", "volume": "20", "issue": "21", "pages": "2222-2224" }, { "id": "authors:7cd2m-b8q69", "collection": "authors", "collection_id": "7cd2m-b8q69", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ANXol95", "type": "article", "title": "Experimental characterization of an angle-multiplexed holographic memory", "author": [ { "family_name": "An", "given_name": "Xin", "clpid": "An-Xin" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We demonstrate a simple angle-multiplexing holographic storage system, using a single acousto-optic deflector to achieve fast random access to the stored holograms. We used this system to store as many as 300 holograms in a 90 degree-geometry Fe:LiNbO3 crystal. To characterize the system performance, we analyzed the reconstructions in terms of the signal-to-noise ratio.", "issn": "0146-9592", "publisher": "Optical Society of America", "publication": "Optics Letters", "publication_date": "1995-09-15", "series_number": "18", "volume": "20", "issue": "18", "pages": "1913-1915" }, { "id": "authors:79a0f-5tp40", "collection": "authors", "collection_id": "79a0f-5tp40", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LIHjosaa95", "type": "article", "title": "Alignment sensitivity of holographic three-dimensional disks", "author": [ { "family_name": "Li", "given_name": "Hsin-Yu Sidney", "clpid": "Li-H-Y-S" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We describe the rotational alignment sensitivity of three-dimensional holographic disks. It is shown that the reconstructed image always rotates by the angle by which the disk rotates; however, the center and the radius of rotation change as the recording geometry changes. A comparison among image plane, Fourier plane, and Fresnel holograms is given, and an optimum configuration (in terms of alignment sensitivity) in which the radius of rotation is zero is derived. We present experimental results and also discuss how the rotation alignment sensitivity affects the storage density and the readout\u2013recording speed of the three-dimensional disk. A brief summary of other sources of misalignment is given.", "doi": "10.1364/JOSAA.12.001902", "issn": "1084-7529", "publisher": "Optical Society of America", "publication": "Journal of the Optical Society of America A", "publication_date": "1995-09", "series_number": "9", "volume": "12", "issue": "9", "pages": "1902-1912" }, { "id": "authors:ybhg4-rnf94", "collection": "authors", "collection_id": "ybhg4-rnf94", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LUOieeeptl95", "type": "article", "title": "High-responsivity optical FET's fabricated on a FET-SEED structure", "author": [ { "family_name": "Luo", "given_name": "Jiafu", "clpid": "Luo-Jiafu" }, { "family_name": "Grot", "given_name": "Annette", "clpid": "Grot-A" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "Optical detectors with responsivity of 1000 A/W and response time of 10 \u03bcs at 50 nW optical input power were fabricated using the AT&T FET-SEED process.", "doi": "10.1109/68.393197", "issn": "1041-1135", "publisher": "IEEE Photonics Technology Letters", "publication": "IEEE Photonics Technology Letters", "publication_date": "1995-07", "series_number": "7", "volume": "7", "issue": "7", "pages": "760-762" }, { "id": "authors:pdwz1-rqe47", "collection": "authors", "collection_id": "pdwz1-rqe47", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:PSAol95", "type": "article", "title": "Holographic storage using shift multiplexing", "author": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Levene", "given_name": "Michael", "clpid": "Levene-M" }, { "family_name": "Pu", "given_name": "Allen", "clpid": "Pu-A" }, { "family_name": "Barbastathis", "given_name": "George", "clpid": "Barbastathis-G" }, { "family_name": "Curtis", "given_name": "Kevin", "clpid": "Curtis-K" } ], "abstract": "We demonstrate theoretically and experimentally a new multiplexing method for volume holographic storage using a single reference beam that is composed of multiple plane waves or is a spherical wave. We multiplex the holograms by shifting the recording material or the recording/readout head. The volume properties of the recording medium allow selective readout of holograms stored in successive overlapping locations. High storage densities can be achieved with a relatively simple implementation by use of the new method.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "1995-04-01", "series_number": "7", "volume": "20", "issue": "7", "pages": "782-784" }, { "id": "authors:8fhx2-yzj84", "collection": "authors", "collection_id": "8fhx2-yzj84", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20171107-160403467", "type": "article", "title": "Three-dimensional disk-based optical correlator", "author": [ { "family_name": "Curtis", "given_name": "Kevin", "clpid": "Curtis-K-R" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "A total of 300 templates were stored as angularly multiplexed transmission holograms at multiple spots on a photopolymer disk. A novel correlator architecture is described and demonstrated that correlates all the templates against an input image within one disk rotation (\u2248 20 ms). The projected performance of the system is 150,000 templates per disk and a processing rate of approximately 6000 correlations per second.", "doi": "10.1117/12.183398", "issn": "0091-3286", "publisher": "Society of Photo-Optical Instrumentation Engineers", "publication": "Optical Engineering", "publication_date": "1994-12", "series_number": "12", "volume": "33", "issue": "12", "pages": "4051-4054" }, { "id": "authors:rb49v-msf92", "collection": "authors", "collection_id": "rb49v-msf92", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CURol94a", "type": "article", "title": "Cross talk for angle- and wavelength-multiiplexed image plane holograms", "author": [ { "family_name": "Curtis", "given_name": "Kevin", "clpid": "Curtis-K" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "The cross talk for image plane holograms is calculated and compared with previously derived results for Fourier plane holograms. Image plane storage is found to have significantly smaller cross talk.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "1994-11-01", "series_number": "21", "volume": "19", "issue": "21", "pages": "1774-1776" }, { "id": "authors:3aec3-2pz06", "collection": "authors", "collection_id": "3aec3-2pz06", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CURao94", "type": "article", "title": "Characterization of the DuPont photopolymer for three-dimensional holographic storage", "author": [ { "family_name": "Curtis", "given_name": "Kevin", "clpid": "Curtis-K" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "DuPont's HRF-150 photopolymer film is investigated for use in three-dimensional holographic memories. Measurements of sensitivity, hologram persistence, the lateral spread of the photoinitiated reaction, and the variation of diffraction efficiency with modulation depth, spatial frequency and tilt angle, and intensity are reported. We observed that the diffraction efficiency of the HRF-150 photopolymer for a given exposure decreases with increases in intensity and grating tilt angle. The holograms were nondestructively reconstructed for long periods of time at room temperature. The photoinitiated reaction spread less than 100 \u00b5m over a period of 16 h.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1994-08-10", "series_number": "23", "volume": "33", "issue": "23", "pages": "5396-5399" }, { "id": "authors:gkhp1-yt558", "collection": "authors", "collection_id": "gkhp1-yt558", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CURol94b", "type": "article", "title": "Method for holographic storage using peristrophic multiplexing", "author": [ { "family_name": "Curtis", "given_name": "Kevin", "clpid": "Curtis-K" }, { "family_name": "Pu", "given_name": "Allen", "clpid": "Pu-A" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "A method of multiplexing holograms by rotating the material or, equivalently, the recording beams is described. Peristropic (Greek for rotation) multiplexing can be combined with other multiplexing methods to increase the storage density of holographic storage systems. Peristrophic multiplexing is experimentally demonstrated with Du Pont's HRF-150 photopolymer film. We multiplexed a total of 295 holograms in a 38-\u03bcm-thick photopolymer film by combining peristrophic multiplexing with angle multiplexing.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "1994-07-01", "series_number": "13", "volume": "19", "issue": "13", "pages": "993-994" }, { "id": "authors:sc7g3-gtf47", "collection": "authors", "collection_id": "sc7g3-gtf47", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LIHao94", "type": "article", "title": "Three-dimensional holographic disks", "author": [ { "family_name": "Li", "given_name": "Hsin-Yu Sidney", "clpid": "Li-H-Y-S" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We describe optical disks that store data holographically in three dimensions by using either angle multiplexing or wavelength multiplexing. Data are stored and retrieved in parallel blocks or pages, and each page consists of approximately 106 bits. The storage capacity of such disks is derived as a function of disk thickness, pixel size, page size, and scanning parameters. The optimum storage density is approximately 120 bits/\u00b5m^2 .", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1994-06-10", "series_number": "17", "volume": "33", "issue": "17", "pages": "3764-3774" }, { "id": "authors:xpmpm-f6m10", "collection": "authors", "collection_id": "xpmpm-f6m10", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ORLapl94", "type": "article", "title": "Spatial and temporal characteristics of electrically fixed holograms in photorefractive strontium-barium niobate", "author": [ { "family_name": "Orlov", "given_name": "Sergei", "clpid": "Orlov-S-S" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Neurgaonkar", "given_name": "Ratnakar R.", "clpid": "Neurgaonkar-R-R" } ], "abstract": "We report measurements of the holographic diffraction efficiency (HDE) of single photorefractive gratings fixed by an externally applied voltage pulse in Sr0.75Ba0.25Nb2O6. The polarization grating HDE and decay rate are strongly dependent on the grating spacing and also depend on the intensity of the light beams during the recording and erasing/reconstruction process. Knowledge of the dependence of the fixing process on spatial frequency may be useful for the creation of physical models of local polarization switching in ferroelectrics.", "doi": "10.1063/1.111026", "issn": "0003-6951", "publisher": "Applied Physics Letters", "publication": "Applied Physics Letters", "publication_date": "1994-02-14", "series_number": "7", "volume": "64", "issue": "7", "pages": "824-826" }, { "id": "authors:jqgyx-k9833", "collection": "authors", "collection_id": "jqgyx-k9833", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:PSAol94", "type": "article", "title": "Nonvolatile storage in photorefractive crystals", "author": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Mok", "given_name": "Fai", "clpid": "Mok-F-H" }, { "family_name": "Li", "given_name": "Hsin-Yu Sidney", "clpid": "Li-H-Y-S" } ], "abstract": "We propose and demonstrate a nonvolatile holographic recording system for storing two-dimensional images. The readout light in this system is not absorbed by the holographic medium, and the data are preformatted or postformatted so that lines from different holograms are interleaved to satisfy the Bragg-matching condition.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "1994-02-01", "series_number": "3", "volume": "19", "issue": "3", "pages": "210-212" }, { "id": "authors:820e1-ty634", "collection": "authors", "collection_id": "820e1-ty634", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CURjosaa93", "type": "article", "title": "Cross talk in phase-coded holographic memories", "author": [ { "family_name": "Curtis", "given_name": "Kevin", "clpid": "Curtis-K" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "The cross talk between holograms multiplexed with Walsh-Hadamard phase codes is analyzed. Each hologram is stored with a reference beam that consists of N phase-coded plane waves. The signal-to-noise ratio (SNR) is calculated for a recording schedule for which the center of each stored image coincides with the nulls of the selectivity function for the adjacent plane-wave components of the reference beam. The SNR characteristics for phase coding with Walsh-Hadamard phase codes are then compared with the SNR for angle and wavelength multiplexing.", "issn": "1084-7529", "publisher": "Optical Society of America", "publication": "Journal of the Optical Society of America A", "publication_date": "1993-12", "series_number": "12", "volume": "10", "issue": "12", "pages": "2547-2550" }, { "id": "authors:k194y-p7223", "collection": "authors", "collection_id": "k194y-p7223", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ORLapl93", "type": "article", "title": "Dynamic electronic compensation of fixed gratings in photorefractive media", "author": [ { "family_name": "Orlov", "given_name": "Sergei", "clpid": "Orlov-S-S" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Neurgaonkar", "given_name": "Ratnakar R.", "clpid": "Neurgaonkar-R-R" } ], "abstract": "We present a model describing the formation of a photorefractive grating in the presence of photorefractively inactive space-charge modulation. The treatment is based on standard linearized Kukhtarevs equations. The model developed is applied to the interpretation of experimental results on electrical fixing in Sr0.75Ba0.25Nb2O6.", "doi": "10.1063/1.110477", "issn": "0003-6951", "publisher": "Applied Physics Letters", "publication": "Applied Physics Letters", "publication_date": "1993-11-01", "series_number": "16", "volume": "63", "issue": "16", "pages": "2466-2468" }, { "id": "authors:njzab-ynk48", "collection": "authors", "collection_id": "njzab-ynk48", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LIHao93", "type": "article", "title": "Optical network for real-time face recognition", "author": [ { "family_name": "Li", "given_name": "Hsin-Yu Sidney", "clpid": "Li-H-Y-S" }, { "family_name": "Qiao", "given_name": "Yong", "clpid": "Qiao-Y" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "An optical network is described that is capable of recognizing at standard video rates the identity of faces for which it has been trained. The faces are presented under a wide variety of conditions to the system and the classification performance is measured. The system is trained by gradually adapting photorefractive holograms.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1993-09-10", "series_number": "26", "volume": "32", "issue": "26", "pages": "5026-5035" }, { "id": "authors:am7cm-k4645", "collection": "authors", "collection_id": "am7cm-k4645", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:NEIao93a", "type": "article", "title": "Programmable image associative memory using an optical disk and a photorefractive crystal", "author": [ { "family_name": "Neifeld", "given_name": "Mark A.", "clpid": "Neifeld-M-A" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "The optical disk is a computer-addressable binary storage medium with very high capacity. More than 10^10 bits of information can be recorded on a 12-cm-diameter optical disk. The natural two-dimensional format of the data recorded on an optical disk makes this medium particularly attractive for the storage of images and holograms, while parallel access provides a convenient mechanism through which such data may be retrieved. In this paper we discuss a closed-loop optical associative memory based on the optical disk. This system incorporates image correlation, using photorefractive media to compute the best association in a shift-invariant fashion. When presented with a partial or noisy version of one of the images stored on the optical disk, the optical system evolves to a stable state in which those stored images that best match the input are temporally locked in the loop.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1993-08-10", "series_number": "23", "volume": "32", "issue": "23", "pages": "4398-4409" }, { "id": "authors:t0c0d-66279", "collection": "authors", "collection_id": "t0c0d-66279", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CURol93", "type": "article", "title": "Cross talk in wavelength multiplexed holographic memories", "author": [ { "family_name": "Curtis", "given_name": "Kevin", "clpid": "Curtis-K" }, { "family_name": "Gu", "given_name": "Claire", "clpid": "Gu-C" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "The cross talk between wavelength-multiplexed holograms is analyzed. The signal-to-noise ratio (SNR) is calculated for a recording schedule that places the center of each image at the null (in wavelength space) of the adjacent hologram. An asymptotic closed-form expression for the minimum SNR is derived in a general reflection geometry. The reflection geometry with counterpropagating signal and reference beams is shown to have the best SNR.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "1993-06-15", "series_number": "12", "volume": "18", "issue": "12", "pages": "1001-1003" }, { "id": "authors:d4a8t-6py23", "collection": "authors", "collection_id": "d4a8t-6py23", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:QIAol93", "type": "article", "title": "Electrical fixing of photorefractive holograms in Sr0.75Ba0.25Nb2O6", "author": [ { "family_name": "Qiao", "given_name": "Yong", "clpid": "Qiao-Y" }, { "family_name": "Orlov", "given_name": "Sergei", "clpid": "Orlov-S-S" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Neurgaonkar", "given_name": "Ratnakar R.", "clpid": "Neurgaonkar-R-R" } ], "abstract": "Photorefractive holograms stored in Sr0.75Ba0.25Nb2O6 crystals are electrically fixed at room temperature. The fixed holograms can be read out directly or after a positive-voltage pulse is applied that can dramatically enhance the diffraction efficiency. Single gratings as well as images are recorded and fixed.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "1993-06-15", "series_number": "12", "volume": "18", "issue": "12", "pages": "1004-1006" }, { "id": "authors:skdcj-tsf09", "collection": "authors", "collection_id": "skdcj-tsf09", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:WAGao93", "type": "article", "title": "Optical neural networks: an introduction to a special issue by the feature editors", "author": [ { "family_name": "Wagner", "given_name": "Kelvin", "clpid": "Wagner-K-H" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "This feature of Applied Optics is devoted to papers on the optical implementation of neural-network models of computation. Papers are included on optoelectronic neuron array devices, optical interconnection techniques using holograms and spatial light modulators, optical associative memories, demonstrations of optoelectronic systems for learning, classification, and target recognition, and on the demonstration, analysis, and simulation of adaptive interconnections for optical neural networks using photorefractive volume holograms.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1993-03-10", "series_number": "8", "volume": "32", "issue": "8", "pages": "1261-1263" }, { "id": "authors:ptdcf-rmc62", "collection": "authors", "collection_id": "ptdcf-rmc62", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:NEIao93b", "type": "article", "title": "Optical implementations of radial basis classifiers", "author": [ { "family_name": "Neifeld", "given_name": "Mark A.", "clpid": "Neifeld-M-A" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We describe two optical systems based on the radial basis function approach to pattern classification. An optical-disk-based system for handwritten character recognition is demonstrated. The optical system computes the Euclidean distance between an unknown input and 650 stored patterns at a demonstrated rate of 26,000 pattern comparisons/s. The ultimate performance of this system is limited by optical-disk resolution to 10^11 binary operations/s. An adaptive system is also presented that facilitates on-line learning and provides additional robustness.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1993-03-10", "series_number": "8", "volume": "32", "issue": "8", "pages": "1370-1379" }, { "id": "authors:6nzww-v2h32", "collection": "authors", "collection_id": "6nzww-v2h32", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LINao93", "type": "article", "title": "GaAs optoelectronic neuron arrays", "author": [ { "family_name": "Lin", "given_name": "Steven", "clpid": "Lin-Steven" }, { "family_name": "Grot", "given_name": "Annette", "clpid": "Grot-A" }, { "family_name": "Luo", "given_name": "Jiafu", "clpid": "Luo-Jiafu" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "A simple optoelectronic circuit integrated monolithically in GaAs to implement sigmoidal neuron responses is presented. The circuit integrates a light-emitting diode with one or two transistors and one or two photodetectors. The design considerations for building arrays with densities of up to 10^4 cm^-2 are discussed.", "doi": "10.1364/AO.32.001275", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1993-03-10", "series_number": "8", "volume": "32", "issue": "8", "pages": "1275-1289" }, { "id": "authors:0asw7-f9979", "collection": "authors", "collection_id": "0asw7-f9979", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CURao92", "type": "article", "title": "Recording of multiple holograms in photopolymer films", "author": [ { "family_name": "Curtis", "given_name": "Kevin", "clpid": "Curtis-K" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "Multiple images were recorded in DuPont HRF-150 photopolymer as transmission holograms by using angle multiplexing. Agreement with Kogelnik's two-wave diffraction theory for phase gratings, the time considerations and its effect on dynamic range, the necessity of a pre-illumination pulse, and good image quality at readout are reported.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1992-12-10", "series_number": "35", "volume": "31", "issue": "35", "pages": "7425-7428" }, { "id": "authors:2vvsa-wt120", "collection": "authors", "collection_id": "2vvsa-wt120", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:QIAol02", "type": "article", "title": "Sampled dynamic holographic memory", "author": [ { "family_name": "Qiao", "given_name": "Yong", "clpid": "Qiao-Y" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We report the experimental demonstration of a photorefractive dynamic holographic memory that has a simple feedback architecture stabilized through a novel spatial sampling technique. By using dynamic copying to compensate for photorefractive decay, this memory provides nondestructive readout, selective erasure and rewriting, and real-time adaptation of holograms through an arbitrarily large number of exposures.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "1992-10-01", "series_number": "19", "volume": "17", "issue": "19", "pages": "1376-1378" }, { "id": "authors:r68jb-gty92", "collection": "authors", "collection_id": "r68jb-gty92", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BRAjosaa92", "type": "article", "title": "Control of volume holograms", "author": [ { "family_name": "Brady", "given_name": "David", "clpid": "Brady-D-J" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "The mismatch in the number of degrees of freedom supported by volume holograms and the boundary fields that control them limits the dynamic range of recorded holograms. For holograms controlled by using fractal sampling grids, the maximum dynamic range falls inversely with the minimum number of exposures needed to record the hologram, the rank of the hologram. In adaptive holography, feedback between coupled holograms prevents the dynamic range from decreasing faster than the fundamental limit. If the control problem is overcome, the maximum dynamic range that a hologram can support falls inversely with the square root of the rank. In principle, holograms in which the dynamic range falls inversely with the square root of the rank can be recorded by using cross-spectrally coherent polychromatic pulses.", "issn": "1084-7529", "publisher": "Optical Society of America", "publication": "Journal of the Optical Society of America A", "publication_date": "1992-07", "series_number": "7", "volume": "9", "issue": "7", "pages": "1167-1182" }, { "id": "authors:pkg1e-ycb37", "collection": "authors", "collection_id": "pkg1e-ycb37", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:QIAao92", "type": "article", "title": "Local learning algorithm for optical neural networks", "author": [ { "family_name": "Qiao", "given_name": "Yong", "clpid": "Qiao-Y" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "An anti-Hebbian local learning algorithm for two-layer optical neural networks is introduced. With this learning rule, the weight update for a certain connection depends only on the input and output of that connection and a global, scalar error signal. Therefore the backpropagation of error signals through the network, as required by the commonly used back error propagation algorithm, is avoided. It still guarantees, however, that the synaptic weights are updated in the error descent direction. With the apparent advantage of simpler optical implementation this learning rule is also shown by simulations to be computationally effective.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1992-06-10", "series_number": "17", "volume": "31", "issue": "17", "pages": "3285-3288" }, { "id": "authors:sqk6j-8mt16", "collection": "authors", "collection_id": "sqk6j-8mt16", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LIHjap92", "type": "article", "title": "Double grating formation in anisotropic photorefractive crystals", "author": [ { "family_name": "Li", "given_name": "Hsin-Yu", "clpid": "Li-H-Y" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "Double gratings form in anisotropic photorefractive crystals when two plane waves intersecting inside the crystal have both extraordinary and ordinary wave components. The effect can be observed by reading out the two gratings with extraordinary or ordinary light. Experiments confirm the theoretical predictions. The relevance of these results in using photorefractive crystals for holographic storage is discussed.", "doi": "10.1063/1.351260", "issn": "0021-8979", "publisher": "Journal of Applied Physics", "publication": "Journal of Applied Physics", "publication_date": "1992-02-01", "series_number": "3", "volume": "71", "issue": "3", "pages": "1394-1400" }, { "id": "authors:3h789-k2284", "collection": "authors", "collection_id": "3h789-k2284", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:QIAjap91", "type": "article", "title": "Phase-locked sustainment of photorefractive holograms using phase conjugation", "author": [ { "family_name": "Qiao", "given_name": "Yong", "clpid": "Qiao-Y" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Gu", "given_name": "Claire", "clpid": "Gu-C" }, { "family_name": "Hong", "given_name": "John", "clpid": "Hong-J" }, { "family_name": "Yeh", "given_name": "Pochi", "clpid": "Yeh-P" }, { "family_name": "Neurgaonkar", "given_name": "R. R.", "clpid": "Neurgaonkar-R-R" } ], "abstract": "A method for sustaining multiply exposed photorefractive holograms, in a phase-locked fashion, by using a pair of phase-conjugating mirrors is described. It is shown that a steady state exists where the overall diffraction efficiency is independent of the number of holographic exposures and the final holograms are exactly in phase with the initial ones. Both analytical and experimental results are presented.", "doi": "10.1063/1.349055", "issn": "0021-8979", "publisher": "Journal of Applied Physics", "publication": "Journal of Applied Physics", "publication_date": "1991-10-15", "series_number": "8", "volume": "70", "issue": "8", "pages": "4646-4648" }, { "id": "authors:maaad-q7317", "collection": "authors", "collection_id": "maaad-q7317", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:RIAao91", "type": "article", "title": "Acousto-optic signal processors for transmission and reception\n of phased-array antenna signals", "author": [ { "family_name": "Riza", "given_name": "Nabeel A.", "clpid": "Riza-N-A" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "Novel acousto-optic processors for control and signal processing in phased-array antennas are presented. These processors can operate in both the antenna transmit and receive modes. An experimental acousto-optic processor is demonstrated in the laboratory. This optical technique replaces all the phase-shifting devices required in electronically controlled phased-array antennas.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1991-08-10", "series_number": "23", "volume": "30", "issue": "23", "pages": "3294-3303" }, { "id": "authors:4vdv9-7q016", "collection": "authors", "collection_id": "4vdv9-7q016", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BRAao91", "type": "article", "title": "Holographic interconnections in photorefractive waveguides", "author": [ { "family_name": "Brady", "given_name": "David J.", "clpid": "Brady-D-J" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "An architecture for implementing large scale holographic interconnections in photorefractive waveguides is described. Methods for controlling the hologram using unguided light are considered and experimentally demonstrated.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1991-06-10", "series_number": "17", "volume": "30", "issue": "17", "pages": "2324-2333" }, { "id": "authors:aeb6q-tbm55", "collection": "authors", "collection_id": "aeb6q-tbm55", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:GUCjap91", "type": "article", "title": "Dynamics of grating formation in photovoltaic media", "author": [ { "family_name": "Gu", "given_name": "Claire", "clpid": "Gu-C" }, { "family_name": "Hong", "given_name": "John", "clpid": "Hong-J" }, { "family_name": "Li", "given_name": "Hsin-Yu", "clpid": "Li-H-Y" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Yeh", "given_name": "Pochi", "clpid": "Yeh-P" } ], "abstract": "The Kukhtarev equations are solved taking into account the photovoltaic effect and different boundary conditions. In the case of open circuit, the voltage across the crystal is found to vary with a time scale similar to the photorefractive time constant. This effect explains the dynamic behavior observed experimentally.", "doi": "10.1063/1.347299", "issn": "0021-8979", "publisher": "Journal of Applied Physics", "publication": "Journal of Applied Physics", "publication_date": "1991-02-01", "series_number": "3", "volume": "69", "issue": "3", "pages": "1167-1172" }, { "id": "authors:yhvhg-rv435", "collection": "authors", "collection_id": "yhvhg-rv435", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BRAol90", "type": "article", "title": "Periodically refreshed multiply exposed photorefractive holograms", "author": [ { "family_name": "Brady", "given_name": "David", "clpid": "Brady-D-J" }, { "family_name": "Hsu", "given_name": "Ken", "clpid": "Hsu-K" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We describe a method for increasing the diffraction efficiency of multiply exposed photorefractive holograms by periodic copying. The method is experimentally demonstrated with photorefractive and thermoplastic recording media.", "doi": "10.1364/OL.15.000817", "issn": "0146-9592", "publisher": "Optical Society of America", "publication": "Optics Letters", "publication_date": "1990-07-15", "series_number": "14", "volume": "15", "issue": "14", "pages": "817-819" }, { "id": "authors:8egab-7r995", "collection": "authors", "collection_id": "8egab-7r995", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:JICnc90", "type": "article", "title": "Generalizing smoothness constraints from discrete samples", "author": [ { "family_name": "Ji", "given_name": "Chuanyi", "clpid": "Ji-Chuanyi" }, { "family_name": "Snapp", "given_name": "Robert R.", "clpid": "Snapp-R-R" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "We study how certain smoothness constraints, for example, piecewise continuity, can be generalized from a discrete set of analog-valued data, by modifying the error backpropagation, learning algorithm. Numerical simulations demonstrate that by imposing two heuristic objectives \u2014 (1) reducing the number of hidden units, and (2) minimizing the magnitudes of the weights in the network \u2014 during the learning process, one obtains a network with a response function that smoothly interpolates between the training data.", "doi": "10.1162/neco.1990.2.2.188", "issn": "0899-7667", "publisher": "MIT Press", "publication": "Neural Computation", "publication_date": "1990-06", "series_number": "2", "volume": "2", "issue": "2", "pages": "188-197" }, { "id": "authors:d8z5s-n3d71", "collection": "authors", "collection_id": "d8z5s-n3d71", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:PSAao90", "type": "article", "title": "Optical memory disks in optical information processing", "author": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Neifeld", "given_name": "Mark A.", "clpid": "Neifeld-M-A" }, { "family_name": "Yamamura", "given_name": "Alan", "clpid": "Yamamura-A" }, { "family_name": "Kobayashi", "given_name": "Seiji", "clpid": "Kobayashi-S" } ], "abstract": "We describe the use of optical memory disks as elements in optical information processing architectures. The optical disk is an optical memory devicew ith a storage capacity approaching 1010b its which is naturally suited to parallel access. We discuss optical disk characteristics which are important in optical computing systems such as contrast, diffraction efficiency, and phase uniformity. We describe techniques for holographic storage on optical disks and present reconstructions of several types of computer-generated holograms. Various optical information processing architectures are described for applications such as database retrieval, neural network implementation, and image correlation. Selected systems are experimentally demonstrated.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1990-05-10", "series_number": "14", "volume": "29", "issue": "14", "pages": "2038-2057" }, { "id": "authors:dwpy9-c0642", "collection": "authors", "collection_id": "dwpy9-c0642", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HONol90", "type": "article", "title": "Diffraction efficiency of strong volume holograms", "author": [ { "family_name": "Hong", "given_name": "John H.", "clpid": "Hong-J-H" }, { "family_name": "Yeh", "given_name": "Pochi", "clpid": "Yeh-P" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Brady", "given_name": "David", "clpid": "Brady-D-J" } ], "abstract": "We investigate the diffraction efficiency of strong volume holograms in which the coupling parameter is several times that needed for maximum diffraction efficiency. We discuss the implications of our findings on photorefractive implementations of various neural network systems.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "1990-03-15", "series_number": "6", "volume": "15", "issue": "6", "pages": "344-346" }, { "id": "authors:w6d8d-5sg37", "collection": "authors", "collection_id": "w6d8d-5sg37", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150415-105244775", "type": "article", "title": "Holography in artificial neural networks", "author": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Brady", "given_name": "David", "clpid": "Brady-D-J" }, { "family_name": "Gu", "given_name": "Xiang-Guang", "clpid": "Gu-Xiang-Guang" }, { "family_name": "Lin", "given_name": "Steven", "clpid": "Lin-Steven" } ], "abstract": "The dense interconnections that characterize neural networks are most readily implemented using optical signal processing. Optoelectronic 'neurons' fabricated from semiconducting materials can be connected by holographic images recorded in photorefractive crystals. Processes such as learning can be demonstrated using holographic optical neural networks.", "doi": "10.1038/343325a0", "issn": "0028-0836", "publisher": "Nature Publishing Group", "publication": "Nature", "publication_date": "1990-01-25", "series_number": "6256", "volume": "343", "issue": "6256", "pages": "325-330" }, { "id": "authors:hxe6k-qha95", "collection": "authors", "collection_id": "hxe6k-qha95", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:VENieeetit89", "type": "article", "title": "Linear and logarithmic capacities in associative neural networks", "author": [ { "family_name": "Venkatesh", "given_name": "Santosh S.", "clpid": "Venkatesh-S-S" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "A model of associate memory incorporating global linearity and pointwise nonlinearities in a state space of n-dimensional binary vectors is considered. Attention is focused on the ability to store a prescribed set of state vectors as attractors within the model. Within the framework of such associative nets, a specific strategy for information storage that utilizes the spectrum of a linear operator is considered in some detail. Comparisons are made between this spectral strategy and a prior scheme that utilizes the sum of Kronecker outer products of the prescribed set of state vectors, which are to function nominally as memories. The storage capacity of the spectral strategy is linear in n (the dimension of the state space under consideration), whereas an asymptotic result of n/4 log n holds for the storage capacity of the outer product scheme. Computer-simulated results show that the spectral strategy stores information more efficiently. The preprocessing costs incurred in the two algorithms are estimated, and recursive strategies are developed for their computation.", "doi": "10.1109/TWC.2006.256975", "issn": "0018-9448", "publisher": "IEEE Transactions on Information Theory", "publication": "IEEE Transactions on Information Theory", "publication_date": "1989-05-01", "series_number": "3", "volume": "35", "issue": "3", "pages": "558-568" }, { "id": "authors:zrwts-r0z82", "collection": "authors", "collection_id": "zrwts-r0z82", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:PSAol89", "type": "article", "title": "Image correlators using optical memory disks", "author": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Neifeld", "given_name": "Mark A.", "clpid": "Neifeld-M-A" }, { "family_name": "Yamamura", "given_name": "Alan", "clpid": "Yamamura-A" } ], "abstract": "Image correlators are described and experimentally demonstrated that are implemented using optical memory disks to store a large library of reference images.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "1989-05-01", "series_number": "9", "volume": "14", "issue": "9", "pages": "429-431" }, { "id": "authors:tq3gr-w6t44", "collection": "authors", "collection_id": "tq3gr-w6t44", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LEEjap89a", "type": "article", "title": "Volume holographic interconnections with maximal capacity and minimal cross talk", "author": [ { "family_name": "Lee", "given_name": "Hyuk", "clpid": "Lee-H" }, { "family_name": "Gu", "given_name": "Xiang-guang", "clpid": "Gu-X" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "Optical interconnections utilizing volume holography are described. Intrinsic cross-talk effects that limit the number of independent interconnections are identified and analyzed by applying coupled-wave analysis. Sampling grids for removing the first-order cross talk are presented, resulting in a system limited by second- and third-order cross talk only.", "doi": "10.1063/1.342828", "issn": "0021-8979", "publisher": "Journal of Applied Physics", "publication": "Journal of Applied Physics", "publication_date": "1989-03-15", "series_number": "6", "volume": "65", "issue": "6", "pages": "2191-2194" }, { "id": "authors:cesm9-r0y62", "collection": "authors", "collection_id": "cesm9-r0y62", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120615-115025571", "type": "article", "title": "Interference filters as nonlinear decision-making elements for three-spot pattern recognition and associative memories", "author": [ { "family_name": "Wang", "given_name": "L.", "orcid": "0000-0002-9803-166X", "clpid": "Wang-L" }, { "family_name": "Esch", "given_name": "V.", "clpid": "Esch-V" }, { "family_name": "Feinleib", "given_name": "R.", "clpid": "Feinleib-R" }, { "family_name": "Zhang", "given_name": "L.", "clpid": "Zhang-L" }, { "family_name": "Jin", "given_name": "R.", "clpid": "Jin-R" }, { "family_name": "Chou", "given_name": "H. M.", "clpid": "Chou-H-M" }, { "family_name": "Sprague", "given_name": "Robert W.", "clpid": "Sprague-R-W" }, { "family_name": "Macleod", "given_name": "H. Angus", "clpid": "Macleod-H-A" }, { "family_name": "Khitrova", "given_name": "G.", "clpid": "Khitrova-G" }, { "family_name": "Gibbs", "given_name": "Hyatt M.", "clpid": "Gibbs-H-M" }, { "family_name": "Wagner", "given_name": "Kelvin", "clpid": "Wagner-K" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "Simple patterns consisting of three spots (V and \u0393) have been recognized by dividing, shifting, and recombining\nbeams onto bistable ZnS interference filters. This experiment demonstrates AND-gate operation,\ncascading, and a moderate amount of parallelism, but a laser power of several watts was required and the\nresponse times were several milliseconds. An associative memory for fingerprint identification has been\nconstructed using a VanderLugt correlator and an interference filter as a reflective thresholding device.", "doi": "10.1364/AO.27.001715", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1988-05-01", "series_number": "9", "volume": "27", "issue": "9", "pages": "1715-1720" }, { "id": "authors:95pwj-jde77", "collection": "authors", "collection_id": "95pwj-jde77", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:PSAao88", "type": "article", "title": "Adaptive optical networks using photorefractive crystals", "author": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Brady", "given_name": "David", "clpid": "Brady-D-J" }, { "family_name": "Wagner", "given_name": "Kelvin", "clpid": "Wagner-K-H" } ], "abstract": "The capabilities of photorefractive crystals as media for holographic interconnections in neural networks are examined. Limitations on the density of interconnections and the number of holographic associations which can be stored in photorefractive crystals are derived. Optical architectures for implementing various neural schemes are described. Experimental results are presented for one of these architectures.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1988-05-01", "series_number": "9", "volume": "27", "issue": "9", "pages": "1752-1759" }, { "id": "authors:2me9f-w5s33", "collection": "authors", "collection_id": "2me9f-w5s33", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ATHao88", "type": "article", "title": "Optical computing: introduction by the guest editors to the feature in the 1 May 1988 issue", "author": [ { "family_name": "Athale", "given_name": "Ravindra A.", "clpid": "Athale-R-A" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Wagner", "given_name": "Kelvin", "clpid": "Wagner-K-H" } ], "abstract": "The feature in the 1 May 1988 issue of Applied Optics includes a collection of papers originally presented at the 1987 Lake Tahoe Topical Meeting on Optical Computing. These papers emphasize digital optical computing systems, optical interconnects, and devices for optical computing, but analog optical processing is considered as well.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1988-05-01", "series_number": "9", "volume": "27", "issue": "9", "pages": "1641-1642" }, { "id": "authors:4j0z4-1qh50", "collection": "authors", "collection_id": "4j0z4-1qh50", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HANao88", "type": "article", "title": "Real-time programmable acoustooptic synthetic aperture radar processor", "author": [ { "family_name": "Haney", "given_name": "Michael", "clpid": "Haney-M" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "The acoustooptic time-and-space integrating approach to real-time synthetic aperture radar (SAR) processing is reviewed, and novel hybrid optical/electronic techniques, which generalize the basic architecture, are described. The generalized architecture is programmable and has the ability to compensate continuously for range migration changes in the parameters of the radar/target geometry and anomalous platform motion. The new architecture is applicable to the spotlight mode of SAR, particularly for applications in which real-time onboard processing is required.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1988-05-01", "series_number": "9", "volume": "27", "issue": "9", "pages": "1786-1796" }, { "id": "authors:39pfm-m6x31", "collection": "authors", "collection_id": "39pfm-m6x31", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120626-090038005", "type": "article", "title": "Multilayer optical learning networks", "author": [ { "family_name": "Wagner", "given_name": "Kelvin", "clpid": "Wagner-K-H" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "A new approach to learning in a multilayer optical neural network based on holographically interconnected nonlinear devices is presented. The proposed network can learn the interconnections that form a distributed representation of a desired pattern transformation operation. The interconnections are formed in an adaptive and self-aligning fashioias volume holographic gratings in photorefractive crystals. Parallel arrays of globally space-integrated inner products diffracted by the interconnecting hologram illuminate arrays of nonlinear Fabry-Perot etalons for fast thresholding of the transformed patterns. A phase conjugated reference wave interferes with a backward propagating error signal to form holographic interference patterns which are time integrated in the volume of a photorefractive crystal to modify slowly and learn the appropriate self-aligning interconnections. This multilayer system performs an approximate implementation of the backpropagation learning procedure in a massively parallel high-speed nonlinear optical network.", "doi": "10.1364/AO.26.005061", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1987-12-01", "series_number": "23", "volume": "26", "issue": "23", "pages": "5061-5076" }, { "id": "authors:vvpcm-n4764", "collection": "authors", "collection_id": "vvpcm-n4764", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LEEol87", "type": "article", "title": "Photorefractive acoustoelectro-optic correlator", "author": [ { "family_name": "Lee", "given_name": "Hyuk", "clpid": "Lee-H" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "An optical correlator based on acoustoelectro-optic interaction is proposed. The device is experimentally demonstrated with a LiNbO3 crystal in which acoustic waves are launched by a piezoelectric transducer and electric fields are established through the photorefractive effect.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "1987-07-01", "series_number": "7", "volume": "12", "issue": "7", "pages": "459-461" }, { "id": "authors:twbxx-4z132", "collection": "authors", "collection_id": "twbxx-4z132", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190710-142228887", "type": "article", "title": "Optical Neural Computers", "author": [ { "family_name": "Abu-Mostafa", "given_name": "Yaser S.", "clpid": "Abu-Mostafa-Y-S" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "Can computers be built to solve problems, such as recognizing patterns, that entail memorizing all possible solutions? The key may be to arrange optical elements in the same way as neurons are arranged in the brain.", "issn": "0036-8733", "publisher": "Scientific American", "publication": "Scientific American", "publication_date": "1987-03", "series_number": "3", "volume": "256", "issue": "3", "pages": "88-95" }, { "id": "authors:m297g-30a60", "collection": "authors", "collection_id": "m297g-30a60", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HONol86", "type": "article", "title": "Storage capacity of holographic associative memories", "author": [ { "family_name": "Hong", "given_name": "John", "clpid": "Hong-J" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "The storage capacity of holographic associative memories is estimated. An argument based on the available degrees of freedom shows that the number of patterns that can be stored is limited by the space-bandwidth product of the hologram divided by the number of pixels in each pattern. A statistical calculation shows that if we attempt to store associations by multiply exposing the hologram, the cross talk among the stored items severely degrades the output fidelity. This confirms the storage capacity predicted by the degrees-of-freedom argument.", "issn": "0146-9592", "publisher": "Optical Society of America", "publication": "Optics Letters", "publication_date": "1986-12", "series_number": "12", "volume": "11", "issue": "12", "pages": "812-814" }, { "id": "authors:7551b-ybg05", "collection": "authors", "collection_id": "7551b-ybg05", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120627-100550573", "type": "article", "title": "Real-time computer-generated hologram by means of liquid-crystal television spatial light modulator", "author": [ { "family_name": "Mok", "given_name": "Fai", "clpid": "Mok-F-H" }, { "family_name": "Diep", "given_name": "Joseph", "clpid": "Diep-J" }, { "family_name": "Liu", "given_name": "Hua-Kuang", "clpid": "Liu-H-K" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "A novel use of liquid-crystal television (LCTV) is described. It is shown that, if the phase nonuniformity of the LCTV is corrected by a liquid gate, then a simple computer-generated hologram can be written and coherently reconstructed.", "doi": "10.1364/OL.11.000748", "issn": "0146-9592", "publisher": "Optical Society of America", "publication": "Optics Letters", "publication_date": "1986-11", "series_number": "11", "volume": "11", "issue": "11", "pages": "748-750" }, { "id": "authors:nxtnc-m2x65", "collection": "authors", "collection_id": "nxtnc-m2x65", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:PSAao86", "type": "article", "title": "High accuracy computation with linear analog optical systems: a critical study", "author": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Athale", "given_name": "Ravindra A.", "clpid": "Athale-R-A" } ], "abstract": "High accuracy optical processors based on the algorithm of digital multiplication by analog convolution (DMAC) are studied for ultimate performance limitations. Variations of optical processors that perform high accuracy vector-vector inner products are studied in abstract and with specific examples. It is concluded that the use of linear analog optical processors in performing digital computations with DMAC leads to impractical requirements for the accuracy of analog optical systems and the complexity of postprocessing electronics.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1986-09-15", "series_number": "18", "volume": "25", "issue": "18", "pages": "3071-3077" }, { "id": "authors:7kmmb-f5d24", "collection": "authors", "collection_id": "7kmmb-f5d24", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:PSAao85", "type": "article", "title": "Bias-free time-integrating optical correlator using a photorefractive crystal", "author": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Yu", "given_name": "Jeffrey", "clpid": "Yu-J" }, { "family_name": "Hong", "given_name": "John", "clpid": "Hong-J" } ], "abstract": "An acoustooptic time-integrating correlator is demonstrated using a photorefractive crystal as the time-integrating detector.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1985-11-15", "series_number": "22", "volume": "24", "issue": "22", "pages": "3860-3865" }, { "id": "authors:p23j7-e4j29", "collection": "authors", "collection_id": "p23j7-e4j29", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HANao85", "type": "article", "title": "Measurement of the temporal coherence properties of pulsed single-mode laser diodes", "author": [ { "family_name": "Haney", "given_name": "Michael", "clpid": "Haney-M" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "The coherence of a single-mode laser diode, under high-speed pulsed modulation, is limited by instabilities in the lasing wavelength arising from transient phenomena in the junction region of the laser. This paper reports the results of an experiment to characterize the effects of these modal instabilities on the temporal coherence of pulsed laser diodes. The primary intent of the experiment was measurement of the cumulative effect of the modal instabilities on the fringe visibility in interferometric time integrating optical processors. A conclusion of this study is that commercially available laser diodes can be used as pulsed light sources in interferometric applications in which the pulse width of the laser is long compared to its characteristic coherence time constant and short compared to its characteristic thermal time constant. Furthermore, the interpulse modal instability can be minimized by prudent choice of operating conditions.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1985-07-01", "series_number": "13", "volume": "24", "issue": "13", "pages": "1926-1932" }, { "id": "authors:dr4p4-tnw25", "collection": "authors", "collection_id": "dr4p4-tnw25", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:FARao85", "type": "article", "title": "Optical implementation of the Hopfield model", "author": [ { "family_name": "Farhat", "given_name": "Nabil H.", "clpid": "Farhat-N-H" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Prata", "given_name": "Aluizio", "clpid": "Prata-A" }, { "family_name": "Park", "given_name": "Eung", "clpid": "Paek-E" } ], "abstract": "Optical implementation of content addressable associative memory based on the Hopfield model for neural networks and on the addition of nonlinear iterative feedback to a vector-matrix multiplier is described. Numerical and experimental results presented show that the approach is capable of introducing accuracy and robustness to optical processing while maintaining the traditional advantages of optics, namely, parallelism and massive interconnection capability. Moreover a potentially useful link between neural processing and optics that can be of interest in pattern recognition and machine vision is established.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1985-05-15", "series_number": "10", "volume": "24", "issue": "10", "pages": "1469-1475" }, { "id": "authors:f6wef-1kd58", "collection": "authors", "collection_id": "f6wef-1kd58", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:PSAol85", "type": "article", "title": "Optical information processing based on an associative-memory model of neural nets with thresholding and feedback", "author": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Farhat", "given_name": "Nabil", "clpid": "Farhat-N-H" } ], "abstract": "The remarkable collective computational properties of the Hopfield model for neural networks [Proc. Nat. Acad. Sci. USA 79, 2554 (1982)] are reviewed. These include recognition from partial input, robustness, and error-correction capability. Features of the model that make its optical implementation attractive are discussed, and specific optical implementation schemes are given.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "1985-02-01", "series_number": "2", "volume": "10", "issue": "2", "pages": "98-100" }, { "id": "authors:bnf6x-gd649", "collection": "authors", "collection_id": "bnf6x-gd649", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:PSAapl85", "type": "article", "title": "Acousto-electro-optic light modulation", "author": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Lee", "given_name": "Hyuk", "clpid": "Lee-H" }, { "family_name": "Sirat", "given_name": "Gabriel", "clpid": "Sirat-G" } ], "abstract": "The acousto-electro-optic effect is analyzed and demonstrated experimentally. The application of the acousto-electro-optic effect to light modulation and deflection is discussed.", "doi": "10.1063/1.95687", "issn": "0003-6951", "publisher": "Applied Physics Letters", "publication": "Applied Physics Letters", "publication_date": "1985-02-01", "series_number": "3", "volume": "46", "issue": "3", "pages": "215-217" }, { "id": "authors:kzn5f-g5a56", "collection": "authors", "collection_id": "kzn5f-g5a56", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120629-104501096", "type": "article", "title": "Conoscopic holography", "author": [ { "family_name": "Sirat", "given_name": "Gabriel", "clpid": "Sirat-G" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "A new method for recording holograms using incoherent light is described. The method is based on optical propagation through birefringent crystals. Optical methods for the reconstruction of such a hologram are also presented.", "doi": "10.1364/OL.10.000004", "issn": "0146-9592", "publisher": "Optical Society of America", "publication": "Optics Letters", "publication_date": "1985-01", "series_number": "1", "volume": "10", "issue": "1", "pages": "4-6" }, { "id": "authors:ggy16-dv650", "collection": "authors", "collection_id": "ggy16-dv650", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190702-135608926", "type": "article", "title": "Image Normalization by Complex Moments", "author": [ { "family_name": "Abu-Mostafa", "given_name": "Yaser S.", "clpid": "Abu-Mostafa-Y-S" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "The role of moments in image normalization and invariant pattern recognition is addressed. The classical idea of the principal axes is analyzed and extended to a more general definition. The relationship between moment-based normalization, moment invariants, and circular harmonics is established. Invariance properties of moments, as opposed to their recognition properties, are identified using a new class of normalization procedures. The application of moment-based normalization in pattern recognition is demonstrated by experiment.", "doi": "10.1109/tpami.1985.4767617", "issn": "0162-8828", "publisher": "IEEE", "publication": "IEEE Transactions on Pattern Analysis and Machine Intelligence", "publication_date": "1985-01", "series_number": "1", "volume": "7", "issue": "1", "pages": "46-55" }, { "id": "authors:3hgbt-rz712", "collection": "authors", "collection_id": "3hgbt-rz712", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190702-142428282", "type": "article", "title": "Recognitive Aspects of Moment Invariants", "author": [ { "family_name": "Abu-Mostafa", "given_name": "Yaser S.", "clpid": "Abu-Mostafa-Y-S" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "Moment invariants are evaluated as a feature space for pattern recognition in terms of discrimination power and noise tolerance. The notion of complex moments is introduced as a simple and straightforward way to derive moment invariants. Through this relation, properties of complex moments are used to characterize moment invariants. Aspects of information loss, suppression, and redundancy encountered in moment invariants are investigated and significant results are derived. The behavior of moment invariants in the presence of additive noise is also described.", "doi": "10.1109/tpami.1984.4767594", "issn": "0162-8828", "publisher": "IEEE", "publication": "IEEE Transactions on Pattern Analysis and Machine Intelligence", "publication_date": "1984-11", "series_number": "6", "volume": "6", "issue": "6", "pages": "698-706" }, { "id": "authors:stjds-8w148", "collection": "authors", "collection_id": "stjds-8w148", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:PSAao84", "type": "article", "title": "Adaptive acoustooptic filter", "author": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Hong", "given_name": "John", "clpid": "Hong-J" } ], "abstract": "A new adaptive filter utilizing acoustooptic devices in a space integrating architecture is described. Two configurations are presented; one of them, suitable for signal estimation, is shown to approximate the Wiener filter, while the other, suitable for detection, is shown to approximate the matched filter.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1984-10-01", "series_number": "19", "volume": "23", "issue": "19", "pages": "3475-3481" }, { "id": "authors:98td9-w9q71", "collection": "authors", "collection_id": "98td9-w9q71", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170726-174146374", "type": "article", "title": "Two-dimensional optical processing using one-dimensional input devices", "author": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "Two-dimensional optical processing architectures that are implemented with one-dimensional input spatial light modulators are reviewed. The advanced state of the art of available one-dimensional devices and the flexibility that exists in the design of two-dimensional architectures with one-dimensional transducers leads to the implementation of the most powerful and versatile optical processors. Signal and image processing architectures of this type are discussed.", "doi": "10.1109/PROC.1984.12952", "issn": "0018-9219", "publisher": "IEEE", "publication": "Proceedings of the IEEE", "publication_date": "1984-07", "series_number": "7", "volume": "72", "issue": "7", "pages": "962-974" }, { "id": "authors:d1rf3-s8p42", "collection": "authors", "collection_id": "d1rf3-s8p42", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120713-092403805", "type": "article", "title": "Photorefractive incoherent-to-coherent optical converter", "author": [ { "family_name": "Shi", "given_name": "Y.", "clpid": "Shi-Y" }, { "family_name": "Psaltis", "given_name": "D.", "clpid": "Psaltis-D" }, { "family_name": "Marrakchi", "given_name": "A.", "clpid": "Marrakchi-A" }, { "family_name": "Tanguay", "given_name": "A. R., Jr.", "clpid": "Tanguay-A-R-Jr" } ], "abstract": "Photorefractive materials have been extensively used in\nrecent years as real-time recording media for optical holography.(^1,2) One prospective application of real-time holography is in the area of optical information processing; for example, the correlation between two mutually incoherent images has recently been demonstrated in real time in a four-wave mixing\ngeometry. (^3) Often, however, the information to be processed exists only in incoherent form. High performance spatial light modulators(^4) are thus necessary in many optical information processing systems to convert incoherent images to coherent replicas for subsequent processing. We report in this Communication the successful demonstration of real-time incoherent-to-coherent images transduction through the use of holographic recording in photorefractive crystals. Several possible configurations and experimental results are presented.", "doi": "10.1364/AO.22.003665", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1983-12-01", "series_number": "23", "volume": "22", "issue": "23", "pages": "3665-3667" }, { "id": "authors:e94r9-9ap76", "collection": "authors", "collection_id": "e94r9-9ap76", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170727-174338028", "type": "article", "title": "Tracking antenna arrays for near-millimeter waves", "author": [ { "family_name": "Tong", "given_name": "Peter P.", "clpid": "Tong-Peter-P" }, { "family_name": "Neikirk", "given_name": "Dean P.", "clpid": "Neikirk-D-P" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Wagner", "given_name": "Kelvin", "clpid": "Wagner-K-H" }, { "family_name": "Young", "given_name": "Peter E.", "clpid": "Young-P-E" } ], "abstract": "A two-dimensional monolithic array has been developed that gives the elevation and azimuth of point source targets. The array is an arrangement of rows and columns of antennas and bismuth bolometer detectors on a fused quartz substrate. Energy is focused onto the array through a lens placed on the back side of the substrate. At 1.38 mm with a 50 mm diameter objective lens, the array has demonstrated a positioning accuracy of 26 arcmin. In a differential mode this precision improves to 9 arcsec, limited by the mechanics of the rotating stage. This tracking could be automated to a fast two-step procedure where a source is first located to the nearest row and column, and then precisely located by scanning. With signal processing the array should be able to track multiple sources.", "doi": "10.1109/TAP.1983.1143076", "issn": "0096-1973", "publisher": "IEEE", "publication": "IEEE Transactions on Antennas and Propagation", "publication_date": "1983-05", "series_number": "3", "volume": "31", "issue": "3", "pages": "512-515" }, { "id": "authors:58tnj-jx923", "collection": "authors", "collection_id": "58tnj-jx923", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:PSAao82", "type": "article", "title": "Optical image correlation using acoustooptic and charge-coupled devices", "author": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "An optical processing method is presented which allows the correlation of two images to be computed in real time with a 1-D acoustooptic spatial light modulator as the input device. Two-dimensional processing is accomplished by a combination of spatial and temporal integration. The time-integrating processing is performed by a CCD detector that is operated as an optically addressed correlator.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1982-02-01", "series_number": "3", "volume": "21", "issue": "3", "pages": "491-495" }, { "id": "authors:c1m6s-2g867", "collection": "authors", "collection_id": "c1m6s-2g867", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:PSAao81", "type": "article", "title": "Acoustooptic spectral estimation: a statistical analysis", "author": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Kumar", "given_name": "B. V. K. Vijaya", "clpid": "Kumar-B-V-K-V" } ], "abstract": "The power spectral density estimate obtained by an acoustooptic (AO) system is analyzed. We find that the variance of the estimate depends on the ratio T2 /T1, where T1 is the aperture of the AO cell and T2 is the integration time of the detector.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1981-02-15", "series_number": "4", "volume": "20", "issue": "4", "pages": "601-605" }, { "id": "authors:21qqb-r4t10", "collection": "authors", "collection_id": "21qqb-r4t10", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:PSAol79", "type": "article", "title": "Iterative color-multiplexed, electro-optical processor", "author": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Casasent", "given_name": "David", "clpid": "Casasent-D" }, { "family_name": "Carlotto", "given_name": "Mark", "clpid": "Carlotto-M" } ], "abstract": "A noncoherent optical vector-matrix multiplier using a linear LED source array and a linear P-I-N photodiode detector array has been combined with a 1-D adder in a feedback loop. The resultant iterative optical processor and its use in solving simultaneous linear equations are described. Operation on complex data is provided by a novel color-multiplexing system.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "1979-11-01", "series_number": "11", "volume": "4", "issue": "11", "pages": "348-350" }, { "id": "authors:5bh4n-smd52", "collection": "authors", "collection_id": "5bh4n-smd52", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CASol79", "type": "article", "title": "Waveform considerations in space-variant optical processors", "author": [ { "family_name": "Casasent", "given_name": "David", "clpid": "Casasent-D" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "abstract": "The use of coded waveforms in space-variant optical signal processors using coordinate transformations is considered. It is shown that nonlinear transmitted coded signals must be used with such a processor and that this results in novel waveform design and system approaches for radar and communications.", "issn": "0146-9592", "publisher": "Optics Letters", "publication": "Optics Letters", "publication_date": "1979-01-01", "series_number": "1", "volume": "4", "issue": "1", "pages": "18-20" } ]