Microfluidics is a multidisciplinary field that uses minute volumes of liquids to attempt complex functionalities. These complicated functionalities often require manipulating interfaces through external forces. In addition, optics have become a fundamental necessity for most microfluidic devices. We combine these two concepts and call it surface optofluidics. Here, we focus on the advantages of surface optofluidics for the development of a biosensor, specifically focusing on the flexibility and adaptability offered by these techniques.
\r\n\r\nTo introduce the advantages presented by surface optofluidics, devices using droplet electrowetting techniques are discussed. We then discuss biosensing through structured electrodes on surfaces. The electrodes are used to align asymmetric bacteria. The aligned bacteria are detected optically. This method of detection is improved by incorporating two different surface optofluidic methods. Concentration and motion control of the bacterium is demonstrated with electric fields on three dimensionally structured electrodes and an optothermal nanoparticle carpet. Finally, we show preliminary work in the study of single bacterium behavior using nanoparticles as labels to detect its specific alignment in space.
\r\n", "doi": "10.7907/KYZG-3503", "publication_date": "2011", "thesis_type": "phd", "thesis_year": "2011" }, { "id": "thesis:6281", "collection": "thesis", "collection_id": "6281", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:04082011-064907780", "primary_object_url": { "basename": "HSIEH_PhD_thesis_2011.pdf", "content": "final", "filesize": 5320736, "license": "other", "mime_type": "application/pdf", "url": "/6281/1/HSIEH_PhD_thesis_2011.pdf", "version": "v4.0.0" }, "type": "thesis", "title": "Imaging with Second-Harmonic Generation Nanoparticles", "author": [ { "family_name": "Hsieh", "given_name": "Chia-Lung", "clpid": "Hsieh-Chia-Lung" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Perona", "given_name": "Pietro", "clpid": "Perona-P" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Yang", "given_name": "Changhuei", "clpid": "Yang-Changhuei" }, { "family_name": "Painter", "given_name": "Oskar J.", "clpid": "Painter-O" }, { "family_name": "Daraio", "given_name": "Chiara", "clpid": "Daraio-C" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Second-harmonic generation nanoparticles show promise as imaging probes due to their coherent and stable signal with a broad flexibility in the choice of excitation wavelength. In this thesis, we developed and demonstrated barium titanate nanoparticles as second-harmonic radiation imaging probes. We studied the absolute second-harmonic generation efficiency of the nanoparticles on single-particle level. The polarization dependent second-harmonic signal of single nanoparticles was studied in detail. From the measured polar response, we were able to find the orientation of the nanoparticle. We developed a biochemical interface for using the second-harmonic nanoprobes as biomarkers, including in vitro cellular imaging and in vivo live animal imaging. The nanoparticles were surface functionalized with primary amine groups for stable colloidal dispersion. We achieved specific labeling of the second-harmonic nanoprobes via immunostaining where the antibodies were covalently conjugated onto the nanoparticles. We observed no toxicity of the functionalized nanoparticles to biological cells. The coherent second-harmonic signal radiated from the nanoparticles offers opportunities for new imaging techniques. Using interferometric detection, namely harmonic holography, both amplitude and phase of the second-harmonic field can be captured. Through digital beam propagation, three-dimensional field distribution, reflecting three-dimensional distribution of the nanoparticles, can be reconstructed. We achieved a scan-free three-dimensional imaging of nanoparticles in biological cells with sub-micron spatial resolution by using the harmonic holographic microscope. We further exploited the coherent second-harmonic signal for imaging through scattering media by performing optical phase conjugation of the second-harmonic signal. We demonstrated an all-digital optical phase conjugation of the second-harmonic signal originated from a nanoparticle by combining harmonic holography and dynamic computer generated holography using a spatial light modulator. The phase-conjugated second-harmonic scattered field retraced the scattering trajectory and formed a clean focus on the nanoparticle placed inside a scattering medium. The nanoparticle acted as a beacon of light; it helped us find the tailored wavefront for concentrating light at the nanoparticle inside the scattering medium. We also demonstrated imaging through a thin scattering medium by raster-scanning the phase-conjugated focus in the vicinity of the beacon nanoparticle, in which a clear image of a target placed behind a ground glass diffuser was obtained.", "doi": "10.7907/WCS2-FD82", "publication_date": "2011", "thesis_type": "phd", "thesis_year": "2011" }, { "id": "thesis:1719", "collection": "thesis", "collection_id": "1719", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-05102009-103332", "type": "thesis", "title": "Plasmonic Nanoparticles for Optofluidic Applications", "author": [ { "family_name": "Adleman", "given_name": "James Richard", "clpid": "Adleman-James-Richard" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Scherer", "given_name": "Axel", "clpid": "Scherer-A" }, { "family_name": "Yang", "given_name": "Changhuei", "clpid": "Yang-Changhuei" }, { "family_name": "Erickson", "given_name": "David", "clpid": "Erickson-D" }, { "family_name": "Goodwin", "given_name": "David G.", "clpid": "Goodwin-D-G" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "This thesis discusses the application of colloidal particles to optofluidic systems. Colloidal particles can be added as a \"dopant\" to the liquids in these devices to provide functionality that cannot be obtained with homogenous fluids. We examine electrooptic effects in liquid suspensions asymmetric metallic nanoparticles. The theoretical optical properties of gold nanorods and noble metal nanohalfshells are computed and compared with those of actual colloidal dispersions. We discuss the design and fabrication of electro-optic waveguides utilizing these suspensions as the active material. We also study the dynamics of photothermal holograms recorded by nanosecond laser pulses in suspensions of silver nanospheres. Unexpected transients in the grating diffraction efficiency correspond to the nanoscale inhomgeneity of the colloid. Longer timescale decay can be used to measure the thermal conductivity of the liquid as predicted by the established theory of heat conduction. This technique is extended to perform spatial imaging of the thermal diffusivity of immiscible binary liquids. Gold nanosphere coated substrates for microfluidic devices are employed to enable optical actuation of fluids. Nanoparticle absorption of continuous wave laser light was used to trap air bubbles inside partially filled microfluidic channels. Light focused on the array near one side of the trapped bubble will drive a mass flow across the bubble. This evaporative bubble assisted mass transport mechanism can be operated as a pump powered by a stationary laser beam. In addition, the process efficiently separates volatile and non-volatile materials and can concentrate and purify specimens in solution.
\r\n\r\nFinally, several schemes for storing and extracting data from subwavelength volumes using spectral multiplexing of semiconductor quantum dots are explored. We demonstrate microfluidic composition and delivery of cocktails of several colors of quantum dots to act as information packets for optical storage. In addition we analyze imaging at the subwavelength level using a patterned surface of quantum dots. The theoretical performance of such a surface is compared to imaging through nanoapertures as is currently implemented in optofluidic microscopy.
\r\n", "doi": "10.7907/QB6E-2Q64", "publication_date": "2009", "thesis_type": "phd", "thesis_year": "2009" }, { "id": "thesis:5251", "collection": "thesis", "collection_id": "5251", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-09142007-143251", "primary_object_url": { "basename": "thesis_zhenyu.pdf", "content": "final", "filesize": 12717987, "license": "other", "mime_type": "application/pdf", "url": "/5251/1/thesis_zhenyu.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Optofluidic Dye Lasers", "author": [ { "family_name": "Li", "given_name": "Zhenyu", "orcid": "0000-0002-7752-6225", "clpid": "Li-Zhenyu" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Scherer", "given_name": "Axel", "clpid": "Scherer-A" }, { "family_name": "Yang", "given_name": "Changhuei", "clpid": "Yang-Changhuei" }, { "family_name": "Libbrecht", "given_name": "Kenneth George", "clpid": "Libbrecht-K-G" }, { "family_name": "Painter", "given_name": "Oskar J.", "clpid": "Painter-O" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Optofluidic dye lasers refer to a class of liquid dye lasers, usually on a microfabricated device, in which the adaptive nature of the liquid gain medium allows the dynamical control of the laser properties. Miniaturizing liquid dye lasers onto a microfluidic device not only results in compact, easy-to-maintain and safe dye laser systems, but also provides unprecedented optical performances such as precise spatial mode control, low threshold, and automatic fluidic tuning. Equally important, such on-chip liquid laser sources represent an important component for \"lab-on-a-chip\" systems.
\r\n\r\nThis thesis studies the implementations of optofluidic dye lasers on polydimethylsiloxane (PDMS) based microfluidic devices. Replica molding soft lithography was used to fabricate monolithic PDMS devices which contain both wavelength-scale optical structures and large-sized microfluidic channels. We have demonstrated narrow linewidth single mode DFB lasers, simultaneous operation of integrated DFB laser arrays with a single pump, multiple color lasing from the same DFB cavity, continuous mechanical wavelength tuning over a 60nm range, microfluidic wavelength tuning, single mode liquid-core microring lasers using Vernier effect, liquid-cladding evanescent gain DFB lasers, and monolithic integration with PDMS microfluidic circuits. Typical laser thresholds achieved are well within the reach of commercial high power laser diodes, thus enabling the implementations of compact tunable laser sources for portable \u201clab-on-a-chip\u201d devices. The impressive performances, diverse geometries and applications clearly demonstrate the power of optofluidic integration and adaptation.
\r\n\r\n", "doi": "10.7907/AQQR-QG80", "publication_date": "2008", "thesis_type": "phd", "thesis_year": "2008" }, { "id": "thesis:1594", "collection": "thesis", "collection_id": "1594", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-05032006-154541", "primary_object_url": { "basename": "thesis.pdf", "content": "final", "filesize": 3011002, "license": "other", "mime_type": "application/pdf", "url": "/1594/1/thesis.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Classical and Quantum Nonlinear Optical Information Processing", "author": [ { "family_name": "Tsang", "given_name": "Mankei", "orcid": "0000-0001-7173-1239", "clpid": "Tsang-Mankei" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "Yang", "given_name": "Changhuei", "clpid": "Yang-Changhuei" }, { "family_name": "Hong", "given_name": "John Hyunchul", "clpid": "Hong-J-H" }, { "family_name": "Painter", "given_name": "Oskar J.", "clpid": "Painter-O" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "This thesis is a theoretical investigation of the classical and quantum information processing enabled by the advent of modern ultrafast nonlinear optics.
\r\n\r\nChapter 2 and 3 study the propagation of ultrashort optical pulses in optical fibers, and propose two methods of compensating the linear and nonlinear distortions experienced by the pulses, namely, reverse propagation and spectral phase conjugation. Chapter 4 and 5 suggest different schemes that implement spectral phase conjugation.
\r\n\r\nChapter 6 and 7 establish the connection between classical spectral phase conjugation and quantum coincident frequency entanglement. Chapter 6 shows how a spectral phase conjugator can create coincident frequency entangled photon pairs, and Chapter 7 in turn demonstrates how a coincident frequency entanglement generator can perform spectral phase conjugation.
\r\n\r\nThe next three chapters, 8, 9, and 10, focus on quantum spatiotemporal information processing. Chapter 8 studies the temporal properties of entangled photon pair propagation and proposes the concept of quantum temporal imaging. Chapter 9 investigates how optical solitons can be used to perform quantum timing jitter reduction and temporal entanglement, while Chapter 10 applies the same idea to the spatial domain for quantum spatial information processing tasks, such as spatial beam displacement uncertainty reduction and quantum lithography.
\r\n\r\nThe final two chapters return to a couple of miscellaneous problems in classical optics. Chapter 11 shows how a pair of dielectric slabs can amplify the near field of an optical image. Chapter 12 explores the similarities between nonlinear optics and fluid dynamics, and speculates on the possibility of using nonlinear optics experiments to simulate fluid dynamics problems.
", "doi": "10.7907/BG6Y-VX33", "publication_date": "2006", "thesis_type": "phd", "thesis_year": "2006" }, { "id": "thesis:1621", "collection": "thesis", "collection_id": "1621", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-05052005-131822", "primary_object_url": { "basename": "ThesisTeTe.pdf", "content": "final", "filesize": 2013868, "license": "other", "mime_type": "application/pdf", "url": "/1621/1/ThesisTeTe.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Operation of Holographic Elements with Broadband Light Sources", "author": [ { "family_name": "Hsieh", "given_name": "Hung-Te", "clpid": "Hsieh-Hung-Te" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Yang", "given_name": "Changhuei", "clpid": "Yang-Changhuei" }, { "family_name": "Hong", "given_name": "John Hyunchul", "clpid": "Hong-J-H" }, { "family_name": "Buse", "given_name": "Karsten", "clpid": "Buse-K" }, { "family_name": "Tai", "given_name": "Yu-Chong", "clpid": "Tai-Yu-Chong" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "This thesis presents the theoretical and experimental investigation of volume holography operated with broadband/polychromatic light sources, i.e., in both continuous-wave (linear) and femtosecond-pulse (nonlinear) regimes.
\r\n\r\nThe first chapter reviews the concept of volume holography and provides a tacit introduction to some basic properties of volume holograms and compares the operation of holograms in the spatial and temporal domains, preparing the readers for later chapters.
\r\n\r\nThe second chapter introduces a powerful theoretical tool for the analysis of volume holograms in the reflection geometry: the matrix formulation, laying the foundation for the application of holographic gratings utilized as WDM filters.
\r\n\r\nThe third chapter takes into consideration the effects of the practically inevitable finite beam-widths. By means of Fourier decomposition, the deviation of the filtering properties of volume holographic gratings from the ideal plane-wave case can be satisfactorily explained and predicted. Experiments and simulations are performed and compared to confirm the validity of the theory.
\r\n\r\nVolume holographic gratings in the reflection geometry serve as excellent WDM filters for telecommunication purposes thanks to their low cross-talk and readily engineered filtering properties. The theoretical design and experimental realization of athermal holographic filters are presented in the fourth chapter. By incorporating a passive, thermally actuated MEMS mirror, the temperature dependence of the Bragg wavelength of a holographic filter can be compensated.
\r\n\r\nThe analysis of holographic gratings in the 90 degree geometry requires a two dimensional theory. The relevant boundary conditions give rise to some peculiar behaviors in this configuration. Theory, simulations and some experimental results of the 90-degree holography are presented in chapter five.
\r\n\r\nThe sixth chapter delves into the subject of instantaneous Kerr index grating established by two intense, interfering femtosecond (pump) pulses at 388 nm owing to the omnipresent third-order nonlinearity. The coupled-mode equations describing the incident and diffracted (probe) pulses at 776 nm are written down; the solution is experimentally corroborated. It is further demonstrated that the temporal resolution in such a holographic pump-probe configuration does not degrade appreciably as the angular separation between pump pulses increases.
\r\n\r\nChapter seven investigates the nonlinear absorption processes in lithium niobate crystals with femtosecond pulses. The model of two-photon absorption well explains and anticipates the transmission coefficients of single pulses over a wide range of intensity. Collinear pump-probe transmission experiments are then carried out to look into the nonlinear absorption suffered by the probe pulse at 776 nm owing to the pump pulse at 388 nm; the dependence of the probe pulse transmission coefficient on the time delay between pump and probe pulses is characterized by a dip and a long-lasting plateau, which are attributed, respectively, to direct two-photon transitions involving pump and probe photons and the existence of free carriers.
\r\n\r\nBuilding on the experimental experience and theoretical understanding of the previous two chapters, the results of holographic pump-probe experiments in lithium niobate crystals are presented in the final chapter. The behavior is much more complicated because it encompasses all phenomena explored in the two preceding chapters, i.e., both the real and imaginary parts of the third-order susceptibility come into play in the instantaneous material response; furthermore, another mixed grating due to excited charge carriers exists long after the pump pulses pass through. Valuable information on the grating formation process is obtained thanks to the sub-picosecond temporal resolution of such configurations.
", "doi": "10.7907/9R5R-JT19", "publication_date": "2005", "thesis_type": "phd", "thesis_year": "2005" }, { "id": "thesis:2100", "collection": "thesis", "collection_id": "2100", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-05262005-174627", "primary_object_url": { "basename": "01_Thesis_Centurion.pdf", "content": "final", "filesize": 4384306, "license": "other", "mime_type": "application/pdf", "url": "/2100/1/01_Thesis_Centurion.pdf", "version": "v4.0.0" }, "type": "thesis", "title": "Study of the Nonlinear Propagation of Femtosecond Laser Pulses", "author": [ { "family_name": "Centurion Mac Lean", "given_name": "Martin", "orcid": "0000-0002-5662-2293", "clpid": "Centurion-Mac-Lean-Martin" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "Scherer", "given_name": "Axel", "clpid": "Scherer-A" }, { "family_name": "Vahala", "given_name": "Kerry J.", "clpid": "Vahala-K-J" }, { "family_name": "Cross", "given_name": "Michael Clifford", "clpid": "Cross-M-C" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "This work presents a comprehensive study of the propagation of femtosecond pulses and the formation and evolution of spatial solitons. The first half (Chapters 2-3) is devoted to the implementation of a novel ultrafast holographic system to capture the nonlinear propagation of laser pulses with femtosecond resolution. Femtosecond pulses are used to record holograms of the ultrafast changes in the material properties. Amplitude and phase changes of the laser beam inside the medium are reconstructed numerically. The strength of the nonlinear material response and the density of free electrons can be recovered from the phase information in the hologram. A single hologram can be captured with fine spatial resolution, or a time-sequence of holograms can be captured in a single shot with reduced spatial resolution. We have observed dramatic differences in the light propagation depending on the material properties.
\r\n\r\nThe second part of the thesis (Chapters 4-5) covers the formation and evolution of spatial solitons in a Kerr medium. We have measured the evolution of the beam profile as a function of pulse energy and propagation length. The optical beam breaks up into a pattern of connected lines (constellation) and self-focused spots (solitons). The solitons self-focus to a minimum diameter and release their excess energy through conical emission, which in turn overlaps with the background constellation and seeds the formation of new solitons. The solitons also show a collective self-organizing behavior caused by their mutual interactions. The evolution of 1-D arrays of solitons was captured using Femtosecond Time-resolved Optical Polarigraphy, a technique that measures the transient birefringence induced by the pulses in the medium. When the array was generated in an unstable configuration, the solitons re-arranged themselves into an array with a (larger) more stable period. A transition to a chaotic state is observed when the input power is increased above a threshold level. A time-averaged pulse propagation equation was used to numerically solve for evolution of the beam. There was good agreement between the experimental results and the computer simulation.
", "doi": "10.7907/AZNE-B514", "publication_date": "2005", "thesis_type": "phd", "thesis_year": "2005" }, { "id": "thesis:1107", "collection": "thesis", "collection_id": "1107", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-03252003-104132", "primary_object_url": { "basename": "Thesis_Yunping_Yang.PDF", "content": "final", "filesize": 1048938, "license": "other", "mime_type": "application/pdf", "url": "/1107/2/Thesis_Yunping_Yang.PDF", "version": "v4.0.0" }, "type": "thesis", "title": "Holographic Recording and Dynamic Range Improvement in Lithium Niobate Crystals", "author": [ { "family_name": "Yang", "given_name": "Yunping", "clpid": "Yang-Yunping" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Adibi", "given_name": "Ali", "clpid": "Adibi-A" }, { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "Vahala", "given_name": "Kerry J.", "clpid": "Vahala-K-J" }, { "family_name": "Chao", "given_name": "Tien-hsin", "clpid": "Chao-Tien-hsin" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "This thesis presents the results of research centered on the topic of improvement of dynamic range and sensitivity in volume holographic recording using photorefractive lithium niobate crystals. In general, there are two approaches to improving the dynamic range. One is at system level, the other approach is at material level. The second chapter compares the system performances of two holographic recording geometries (the 90-degree and transmission geometries) using iron-doped lithium niobate. The comparison is based on dynamic range, sensitivity, scattering noise, inter-pixel noise, and storage capacity. The third chapter investigates dark decay mechanisms in lithium niobate crystals. Two mechanisms of the dark decay, proton compensation and electron tunneling with activation energies of 1.0 eV and 0.28 eV, respectively, are identified. In crystals with low doping levels, proton compensation dominates the dark decay and extrapolation of lifetimes by an Arrhenius law to room temperature is valid. The time constant of this type of dark decay is inversely proportional to the proton concentration. For crystals with high doping levels, electron tunneling dominates the dark decay. This type of dark decay also limits the highest practical doping level in LiNbO3 crystals. For crystals with medium doping levels, both proton compensation and electron tunneling contribute significantly to the dark decay, and the single Arrhenius law does not hold with a single activation energy. In the fourth chapter, holographic data storage experiments are performed using manganese-doped lithium niobate crystals. The idea to use manganese-doped lithium niobate crystals for holographic storage is the direct result of the understanding of dark decay mechanisms discussed in Chapter 3. The experimental results of dark decay, M/#, sensitivity, multiplexing, thermal fixing, and holographic scattering for LiNbO3 : 0.2 atomic% Mn and LiNbO3 : 0.5 wt% MnCO3 are presented. The experimental results show that manganese-doped lithium niobate crystals are well suited for holographic storage. In the final chapter attention is focused on photorefractive properties of manganese-doped lithium niobate crystals. Material parameters, such as the distribution coefficient, are determined. Absorption measurements are used to obtain some information about several charge transport parameters. The dynamic range (M/#) and sensitivity for crystals of different doping levels, different oxidation states, and for different light polarizations have been measured.\r\n", "doi": "10.7907/V631-NJ22", "publication_date": "2003", "thesis_type": "phd", "thesis_year": "2003" }, { "id": "thesis:1527", "collection": "thesis", "collection_id": "1527", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-04282003-142947", "primary_object_url": { "basename": "MyThesis.pdf", "content": "final", "filesize": 7129710, "license": "other", "mime_type": "application/pdf", "url": "/1527/1/MyThesis.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Holographic Information Systems", "author": [ { "family_name": "Panotopoulos", "given_name": "Georgios", "clpid": "Panotopoulos-Georgios" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Abu-Mostafa", "given_name": "Yaser S.", "clpid": "Abu-Mostafa-Y-S" }, { "family_name": "Buse", "given_name": "Karsten", "clpid": "Buse-K" }, { "family_name": "Painter", "given_name": "Oskar J.", "clpid": "Painter-O" }, { "family_name": "Vahala", "given_name": "Kerry J.", "clpid": "Vahala-K-J" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The goal of this work is to investigate the use of holographic techniques for information processing and transmission systems. Until recently information has been processed and transmitted mainly electronically. With the advent of optical fiber communications the monopoly of electronics has receded in the telecommunications field, but the domain of information processing is still dominated by electronic processors.
\r\n\r\nThis thesis follows a top-down approach to the design of processors that integrate both electronic and optical components. It begins with the design considerations of a compact, rapidly reconfigurable opto-electronic processor, which possesses an optical bus in addition to the traditional electronic bus. The optical bus takes advantage of the massive parallelism that is afforded by optics and can be coupled to a holographic digital memory, allowing rapid reconfiguration of the device. The capability of rapid reconfiguration gives rise to a new computational paradigm, where the reprogramming of the device can become part of the computation. We suggest additional applications of this processor, namely as a smart reading head for large scale holographic disk memories. Finally we present novel algorithms that were developed specifically to take advantage of the additional capabilities of our processor.
\r\n\r\nThe next section is concerned with the wavelength and angular tuning of strong volume holograms, both in the reflection and 90-degree geometries. Since photons have no charge, we need to rely on their wave properties to manipulate them, both for long-range transmission, such as telecommunications, and short-range transmission, such as on chip interconnects. In this section we investigate how volume holograms can be used to selectively redirect information bearing light beams.
\r\n\r\nThe final part of this thesis is concerned with material issues. Holographic recording of strong volume gratings is one of the most commonly used approaches, and photorefractive materials have a strong bearing on the overall performance of the final system. Two properties of iron doped lithium niobate are investigated, namely the dependence of absorption on temperature and the quadratic electro-optic coefficient. The former is crucial for the commonly used technique of thermal fixing, and the latter can become significant should we choose to use applied continuous fields to tune our gratings.
", "doi": "10.7907/P6B7-VR22", "publication_date": "2003", "thesis_type": "phd", "thesis_year": "2003" }, { "id": "thesis:6358", "collection": "thesis", "collection_id": "6358", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:04272011-110550070", "primary_object_url": { "basename": "Liu_z_2002.pdf", "content": "final", "filesize": 55483438, "license": "other", "mime_type": "application/pdf", "url": "/6358/1/Liu_z_2002.pdf", "version": "v6.0.0" }, "type": "thesis", "title": "Optical Information Storage and Processing", "author": [ { "family_name": "Liu", "given_name": "Zhiwen", "clpid": "Liu-Zhiwen" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" }, { "family_name": "Perona", "given_name": "Pietro", "orcid": "0000-0002-7583-5809", "clpid": "Perona-P" }, { "family_name": "Quake", "given_name": "Stephen R.", "clpid": "Quake-S-R" }, { "family_name": "Tai", "given_name": "Yu-Chong", "orcid": "0000-0001-8529-106X", "clpid": "Tai-Yu-Chong" }, { "family_name": "Vahala", "given_name": "Kerry J.", "orcid": "0000-0003-1783-1380", "clpid": "Vahala-K-J" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Optical information storage and optical information processing are the two themes of this thesis. Chapter two and three discuss the issue of storage while the final two chapters investigate the topic of optical computing.\r\n\r\nIn the second chapter, we demonstrate a holographic system which is able to record phenomena in nanosecond speed. Laser induced shock wave propagation is recorded by\r\nangularly multiplexing pulsed holograms. Five frames can be recorded with frame interval of 12ns and time resolution of 5.9ns. We also demonstrate a system which can record fast\r\nevents holographically on a CCD camera. Carrier multiplexing is used to store 3 frames in a single CCD frame with frame interval of 12ns. This technique can be extended to record femtosecond events.\r\n\r\nInformation storage in subwavelength structures is discussed in the third chapter. A 2D simulation tool using the FDTD algorithm is developed and applied to calculate the far field scattering from subwavelength trenches. The simulation agrees with the experimental data very well. Width, depth and angle multiplexing is investigated to encode information in subwavelength features. An eigenfunction approach is adopted to analyze how much\r\ninformation can be stored given the length of the feature. Finally we study the effect of nonlinear buffer layer.\r\n\r\nWe switch gear to holographic correlators in the fourth chapter. We study various properties of the defocused correlator which can control the shift invariance conveniently. An approximate expression of the shift selectivity is derived. We demonstrate a real time\r\ncorrelator with 480 templates. The cross talk of the correlators is also analyzed.\r\n\r\nFinally, in the fifth chapter we apply the optical correlator to fingerprint identification and study the performance of the correlation based algorithms. The windowed correlation can improve the rotation and distortion tolerance.", "doi": "10.7907/EVK8-H316", "publication_date": "2002", "thesis_type": "phd", "thesis_year": "2002" }, { "id": "thesis:6372", "collection": "thesis", "collection_id": "6372", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05042011-091003477", "primary_object_url": { "basename": "Mumbru_j_2002.pdf", "content": "final", "filesize": 59845945, "license": "other", "mime_type": "application/pdf", "url": "/6372/1/Mumbru_j_2002.pdf", "version": "v5.0.0" }, "type": "thesis", "title": "Optoelectronic Circuits Using Holographic Elements", "author": [ { "family_name": "Mumbr\u00fa", "given_name": "Jos\u00e9", "clpid": "Mumbr\u00fa-Jos\u00e9" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" }, { "family_name": "Bossaerts", "given_name": "Peter L.", "clpid": "Bossaerts-P-L" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" }, { "family_name": "Mok", "given_name": "Fai H.", "clpid": "Mok-Fai-H" }, { "family_name": "Perona", "given_name": "Pietro", "orcid": "0000-0002-7583-5809", "clpid": "Perona-P" }, { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "This thesis presents the results of research in the use of holographic modules in optoelectronic systems, their applications, and the characterization of polymer materials on which to record volume holograms, for these modules. The first chapter makes the case that a direct interface between an optical memory and a chip integrating detectors and logic circuitry can better utilize the high parallelism inherent in holographic modules.\r\n\r\nThe second chapter introduces the idea of reconfigurable computing and Field Programmable Gate Arrays (FPGAs) as the framework in which to design a hybrid system, the\r\nOptically Programmable Gate Array (OPGA), that outperforms its electronic counterpart by reducing its reconfiguration time by three orders of magnitude. \r\n\r\nThe OPGA is the combination of three elements: an addressing device to selectively recall holographic data pages, an optical memory, and an optoelectronic chip. The third chapter investigates the issues related to each one of these elements and their integration in a compact module. Operation of the system is demonstrated by holographically programming the OPGA chip.\r\n\r\nIn the fourth chapter, experiments are performed to characterize the Aprilis ULSH500-7A photopolymer and study quantitatively its ability to store high-bandwidth\r\nholographic data pages. A method for hologram mastering and copying using Aprilis films is also demonstrated.\r\n\r\nChapter five investigates the recording and diffusional-amplification dynamics of the PQ-doped PMMA polymer. Different strategies to optimize the material by reducing\r\nthe duration of its post-exposure are examined, and the corresponding experimental results presented. The recording of strong gratings in samples of PQ-PMMA is tested to determine the suitability of this material for components in optical fiber networks.\r\n\r\nThe final chapter deals with applications and systems that can benefit from a direct interface with a holographic module. The use of optically programmable processors in the\r\nfield of neural prosthetics is explored. The design of a holographic 4-D microscope is presented and tested experimentally.\r\n", "doi": "10.7907/GM6Y-TE35", "publication_date": "2002", "thesis_type": "phd", "thesis_year": "2002" }, { "id": "thesis:6155", "collection": "thesis", "collection_id": "6155", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:10222010-101901467", "primary_object_url": { "basename": "Moser_c_2001.pdf", "content": "final", "filesize": 24379926, "license": "other", "mime_type": "application/pdf", "url": "/6155/1/Moser_c_2001.pdf", "version": "v5.0.0" }, "type": "thesis", "title": "Optical Information Processing", "author": [ { "family_name": "Moser", "given_name": "Christophe", "clpid": "Moser-C" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Unknown", "given_name": "Unknown" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The title of this work Optical Information Processing reflects the multi-facets of this thesis.\r\nIn the first three chapters, I look at specific aspects of optical data storage. Enabled by new recording materials, a read-write holographic memory is explored. The memory combines a two-dimensional layered architecture and holography. Recording dynamics are analyzed and compared with conventional memories. A novel multiplexing\r\nmethod, based on the confinement of spherical waves in waveguides, allows the implementation of fiat read-only memories with no moving parts. Novel polymer films at low temperatures show extremely selective frequency absorption which yields up to hundred thousands of independent frequency channels. This radically different multiplexing scheme is combined with Bragg multiplexing to increase the\r\nstorage density. Femtosecond pulses can be stored and retrieved in these materials. For further processing, a pulse shaper and an all-optical logic capable of processing\r\nTerahertz pulse streams are experimentally demonstrated.\r\nThe last two chapters look at three-dimensional surface measurements. A profilometer and a wavefront sensor based on the propagation of light in birefringent crystals are investigated. The performance of both sensors is theoretically modeled and experimentally verified. A third sensor is designed for an ophthalmic application.", "doi": "10.7907/3mvn-0f95", "publication_date": "2001", "thesis_type": "phd", "thesis_year": "2001" }, { "id": "thesis:308", "collection": "thesis", "collection_id": "308", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-01232009-094031", "primary_object_url": { "basename": "Steckman_gj_2001.pdf", "content": "final", "filesize": 33454468, "license": "other", "mime_type": "application/pdf", "url": "/308/1/Steckman_gj_2001.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Holographic recording in polymeric materials with applications", "author": [ { "family_name": "Steckman", "given_name": "Gregory Joseph", "clpid": "Steckman-G-J" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "This thesis presents the results of research in volume holographic recording in several polymeric recording materials and their use in selected applications. The first chapter discusses the key properties of holographic recording materials. The second chapter develops a technique for calculating exposure schedules for photorefractive polymers which do not exhibit mono-exponential recording dynamics. It is determined that these materials require performance improvements before they can be successfully applied to many interesting applications of volume holography, such as holographic data storage and optical correlators which are described in later chapters.\r\n\r\nThe third chapter investigates recording in diffusion amplification based polymer materials. This class of materials overcomes many limitations of other polymer types, such as limited thicknesses and volume shrinkage. A new material based on the diffusion amplification principle is developed with the goal of increasing dynamic range. The new material, a naphtoquinone and PMMA based co-polymer, is demonstrated in holographic recording experiments.\r\n\r\nIn the fourth chapter, holographic data storage experiments are performed and a storage density of 7 bits/\u03bcm[superscript 2] is achieved. A holographic data storage system which utilizes shift multiplexing is modeled and simulated to determine optimal system parameters and material characteristics. It is discovered that the dynamic range of the material used, phenanthrenequinone doped poly(methyl methacrylate), is insufficient to provide very high data storage densities.\r\n\r\nIn the fifth chapter attention is focused on the development and characterization of an optical holographic correlator system using the DuPont HRF-150 photopolymer. The system is used for image recognition and tracking. The performance of the system is characterized with multiple 2-d and 3-d objects with respect to camera resolution, magnification, rotation, and other transformations. The system is demonstrated to be capable of simultaneously recognizing and tracking multiple targets, even in the presence of extraneous objects and partial obscuring of the targets.\r\n\r\nThe final chapter describes the development of a high-speed holographic movie camera. Utilizing a Q-switched Nd:YAG pulse laser and Aprilis ULSHSO0-7A recording material, multi-frame holographic exposures with a 80 MHz frame rate are recorded.\r\n", "doi": "10.7907/m10t-n277", "publication_date": "2001", "thesis_type": "phd", "thesis_year": "2001" }, { "id": "thesis:6144", "collection": "thesis", "collection_id": "6144", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:10152010-092145939", "primary_object_url": { "basename": "Liu_W_2001.pdf", "content": "final", "filesize": 17903656, "license": "other", "mime_type": "application/pdf", "url": "/6144/1/Liu_W_2001.pdf", "version": "v5.0.0" }, "type": "thesis", "title": "Holographic resolution and its application in memory and imaging", "author": [ { "family_name": "Liu", "given_name": "Wenhai", "clpid": "Liu-W" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Unknown", "given_name": "Unknown" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Optical information storage and optical information processing are two major applications of holography, with significantly different holographic philosophies. For a\r\nholographic memory system, a complex holographic pattern encoded with the storage data is recorded first, and is read out later by a simple pre-designed reference beam.\r\nFor a holographic information processing system, a pre-designed holographic pattern is stored in the medium first, and is probed by complex incident signal wave fronts.\r\nThe pre-designed hologram extracts certain components from the complex input and diffract them as specific reference wave fronts. Holographic resolution, or Bragg phase\r\nselectivity in spatial and spectral dimensions, plays a key role in both applications. It determines the information capacity to be stored in and reconstructed from the\r\nhologram memory, or the information capacity to be extracted and processed by a hologram from the complex signal input. In this thesis, we investigate the holographic\r\nresolution in volume holograms and its specific issues in both applications.\r\nIn a phase conjugate holographic memory system, we demonstrate the recording and reconstruction of a submicron pixel resolution, leading to the potential of storing 1 Gbit in 1 cm^3 volume holographically. Phase conjugate reconstruction eliminates the optical resolution limit by the imaging optics and reduces the system volume and\r\ncost. Phase conjugate reconstruction and its multiplexing in a compact holographic module are investigated.\r\nIn general, a volume hologram has two degenerate Bragg phase-matching dimensions besides the spatial and spectral selectivity, in which significant diffraction is\r\npresent. They provide a potential ability for optically sectioning a two-dimensional slice from the spatial plus spectral hyperspace and for linearly transferring the information onto a two-dimensional sensor array by a single hologram. The resolution of optical sectioning and information transformation is not only determined by the volume hologram diffraction intensity selectivity but also by the holographic architecture and the transformation aberration.\r\nWe study two holographic architectures theoretically and experimentally, on issues of optical sectioning and linear transformation for imaging application. By designing\r\na transmission geometry system, we have achieved a linear 2-D optical sectioning and imaging from a 4-D object hyperspace (3-D spatial plus spectral dimension). By optical sectioning of multiplexed holograms, the ability of imaging 3-D spatial information from an object without a scanning mechanism is demonstrated by a holographic imaging system.", "doi": "10.7907/BDB0-VJ12", "publication_date": "2001", "thesis_type": "phd", "thesis_year": "2001" }, { "id": "thesis:7366", "collection": "thesis", "collection_id": "7366", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:01032013-152450777", "primary_object_url": { "basename": "billock_jg-2001.pdf", "content": "final", "filesize": 7511479, "license": "other", "mime_type": "application/pdf", "url": "/7366/1/billock_jg-2001.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Attentional Control of Complex Systems", "author": [ { "family_name": "Billock", "given_name": "Joseph Gregory", "clpid": "Billock-Joseph-Gregory" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" }, { "family_name": "Abu-Mostafa", "given_name": "Yaser S.", "clpid": "Abu-Mostafa-Y-S" }, { "family_name": "Koch", "given_name": "Christof", "orcid": "0000-0001-6482-8067", "clpid": "Koch-C" }, { "family_name": "Barbastathis", "given_name": "G.", "clpid": "Barbastathis-G" }, { "family_name": "Perona", "given_name": "Pietro", "orcid": "0000-0002-7583-5809", "clpid": "Perona-P" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "This thesis reports on work done in applying some of the concepts and architectures found in biological computation to computer algorithms. Biology has long inspired computer technology at the level of processing elements. This thesis explores the application of biologically inspired algorithms at a higher level-that of functional structures of the nervous system. The first chapter gives background on the attentional/awareness model of the brain, why it is important to biology and the advantages in real-time performance and in learning facilitation which we expect from applying it in computer algorithms.
\r\n\r\nThe second chapter examines the application of this model to a canonical computer science problem-the bin packing problem. Approaching this NP-complete problem when limited by computational resources and time constraints means that algorithms which throwaway large amounts of the information about the problem perform better than those which attempt to consider everything. The existence of an optimum in the size of a working memory needed to find the best solution under time pressure is shown. The transition between the regime of strict time constraints and more forgiving time constraints is quite sudden. Chapter 3 presents an analytical model for better understanding the performance of various bin packing algorithms.
\r\n\r\nChapter 4 examines the application of the attentional model to a real-time computer game testbed. This testbed is explained, and results are shown which illustrate that in a complex, unpredictable environment with tight time and resource constraints conditions, an algorithm which examines only that information which falls into a relatively small part of the playing area can win against player which addresses it all.
\r\n\r\nChapter 5 turns to an examination of the role of reduced informational representations upon learning. Solving of various logical-kinetic puzzles by a simulated segmented arm is done by a learning system. A logic supervisory subsystem utilizes attentional/awareness methods to train, and pass control of the different control levels of the articulate arm over to, the neural networks, adaptive resonance theory networks, and declarative computer memory which it trains. Finally, chapter 6 presents an overview and evaluation of the work.
", "doi": "10.7907/132r-jm11", "publication_date": "2001", "thesis_type": "phd", "thesis_year": "2001" }, { "id": "thesis:6200", "collection": "thesis", "collection_id": "6200", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:12092010-094455249", "type": "thesis", "title": "Persistent holographic storage in photorefractive crystals", "author": [ { "family_name": "Adibi", "given_name": "Ali", "clpid": "Adibi-Ali" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Unknown", "given_name": "Unknown" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The work presented in this thesis has been focused on solving the most important and long-lasting problem of destructive read-out in holographic recording in photorefractive crystals. Several interesting methods for solving this problem were proposed and demonstrated by researchers for more than two decades. However, none of them\r\nwere practical for read / write applications. The most promising all-optical method, which is still being pursued by some researchers, was two-step recording. However,\r\nthe method suffers from low sensitivity and dynamic range, even in the optimized conditions. Furthermore, several experimental results were not explained due to the\r\nlack of a complete understanding of the dominant phenomena that were involved. Our strategy in solving the problem of destructive read-out of holograms was to first provide a complete understanding of the physics of the two-step recording method by appropriate modeling, and to explain the experimental results that had not been explained before. Such an understanding gave us a good idea about the major problem of the method, and we were able to find a solution to that problem by adding one dopand to the recording crystal. The method we developed both theoretically and experimentally in this thesis is called two-center holographic recording. The initial results of the method (without any optimization) offer more than one order of magnitude (and for some parameters, two orders of magnitude) improvement over the optimized two-step recording method.\r\nIn this thesis, we provide a complete modeling for two-center recording that agrees\r\nvery well with the experimental results, provides us with the understanding of the\r\nmain physical phenomena that are involved, and helps us in optimizing the method.\r\nThe next step is to relate the material and system parameters for the system design.\r\nWe present in this thesis a standard framework for such a relation, and outline the\r\nmain general steps in the system design using two-center recording. The idea developed\r\nin this thesis opens us several avenues for further thinking and research, and\r\nsome of them are already being investigated by different research groups.", "doi": "10.7907/ESSK-6B14", "publication_date": "2000", "thesis_type": "phd", "thesis_year": "2000" }, { "id": "thesis:6102", "collection": "thesis", "collection_id": "6102", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:10052010-160806470", "type": "thesis", "title": "Optoelectric devices for optical memory systems", "author": [ { "family_name": "Wang", "given_name": "Xu", "clpid": "Wang-Xu" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Unknown", "given_name": "Unknown" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "This thesis describes several optoelectronic devices developed for the optical memory system. It consists of three parts, which are liquid crystal beam steering devices,\r\nmodeling and measurement of optical diffraction from subwavelength structure at focused spot, and CMOS detector design.\r\n\r\nIn liquid crystal beam steering devices, two types of liquid crystal beam deflectors have been successfully demonstrated. The essential working idea of those two deflectors is the same, which is utilizing a blazed grating (either permanently fabricated or virtually built up) to deflect the incident beam and the liquid crystal is used as an electrically controllable birefringent medium. The reflective type deflector exploits the liquid crystal on silicon (LCOS) technology to build up a virtual blazed grating (dynamic grating) and vary this virtual grating's period to achieve multiple steering angels. Seven addressable angles with as high as 93% steering efficiency have been demonstrated. A numerical modeling tool is also developed to analyze liquid crystal molecule director's distribution under nonuniform electrical field (fringe-field-effect). The transmission type deflector is based on a custom-fabricated PMMA blazed grating (fixed grating) and dynamically address multiple angles by stacking several layers of PMMA/LC composite gratings. 16 steering angles are obtained with the contrast ratio of 18. A fabrication-compensation trick is proposed to greatly improve the\r\ndevice's performance.\r\n\r\nIn modeling and measurement of optical diffraction from subwavelength structure at focused spot, we describe a technique for studying scattering from subwavelength\r\nfeatures that used a focused ion beam system to generate subwavelength, submicron features and a simple scatterometer to measure the scattering from single subwavelength scatterers. A two-dimensional model that handles arbitrary profiles is described. The model is shown to agree quite well with the experimental measurements.\r\nThe model is then 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 on distinguishing pits from particles do not extend to low aspect ratio features.\r\n\r\nFinally, in CMOS detector, we have designed a CMOS detector to be used in the compact memory module. The chip features 64 x 64 array of 17\u00b5m x 17\u00b5m pixel with 23% filling factor within a 2mm x 2mm die, correlated double sampling (CDS) signalconditioning circuit in each column, as well as the software-controlled window-of-interest readout. Even more, two pixel designs (active photodiode and direct readout photo diode) are incorporated with the same chip for performance comparison.\r\n", "doi": "10.7907/kf9g-xq27", "publication_date": "2000", "thesis_type": "phd", "thesis_year": "2000" }, { "id": "thesis:3108", "collection": "thesis", "collection_id": "3108", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-08132004-133148", "primary_object_url": { "basename": "Levene_m_1998.pdf", "content": "final", "filesize": 8023825, "license": "other", "mime_type": "application/pdf", "url": "/3108/1/Levene_m_1998.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Optics in neural computation", "author": [ { "family_name": "Levene", "given_name": "Michael", "clpid": "Levene-M" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Tanguay", "given_name": "Armand", "clpid": "Tanguay-A" }, { "family_name": "Fraser", "given_name": "Scott E.", "clpid": "Fraser-S-E" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "In all attempts to emulate the considerable powers of the brain, one is struck by both its immense size, parallelism, and complexity. While the fields of neural networks, artificial intelligence, and neuromorphic engineering have all attempted oversimplifications on the considerable complexity, all three can benefit from the inherent scalability and parallelism of optics. This thesis looks at specific aspects of three modes in which optics, and particularly volume holography, can play a part in neural computation.\n\nFirst, holography serves as the basis of highly-parallel correlators, which are the foundation of optical neural networks. The huge input capability of optical neural networks make them most useful for image processing and image recognition and tracking. These tasks benefit from the shift-invariance of optical correlators. In this thesis, I analyze the capacity of correlators, and then present several techniques for controling the amount of shift invariance. Of particular interest is the Fresnel correlator, in which the hologram is displaced from the Fourier plane. In this case, the amount of shift invariance is limited not just by the thickness of the hologram, but by the distance of the hologram from the Fourier plane.\n\nSecond, volume holography can provide the huge storage capacity and high speed, parallel read-out necessary to support large artificial intelligence systems. However, previous methods for storing data in volume holograms have relied on awkward beamsteering or on as-yet non-existent cheap, wide-bandwidth, tunable laser sources. This thesis presents a new technique, shift multiplexing, which is capable of very high densities, but which has the advantage of a very simple implementation. In shift multiplexing, the reference wave consists of a focused spot a few millimeters in front of the hologram. Multiplexing is achieved by simply translating the hologram a few tens of microns or less. This thesis describes the theory for how shift multiplexing works based on an unconventional, but very intuitive, analysis of the optical far-field. A more detailed analysis based on a path-integral interpretation of the Born approximation is also derived. The capacity of shift multiplexing is compared with that of angle and wavelength multiplexing.\n\nThe last part of this thesis deals with the role of optics in neuromorphic engineering. Up until now, most neuromorphic engineering has involved one or a few VLSI circuits emulating early sensory systems. However, optical interconnects will be required in order to push towards more ambitious goals, such as the simulation of early visual cortex. I describe a preliminary approach to designing such a system, and show how shift multiplexing can be used to simultaneously store and implement the immense interconnections required by such a project.\n", "doi": "10.7907/XQVE-SA13", "publication_date": "1998", "thesis_type": "phd", "thesis_year": "1998" }, { "id": "thesis:986", "collection": "thesis", "collection_id": "986", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-03172008-142604", "primary_object_url": { "basename": "Barbastathis_g_1998.pdf", "content": "final", "filesize": 10693439, "license": "other", "mime_type": "application/pdf", "url": "/986/1/Barbastathis_g_1998.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Intelligent holographic databases", "author": [ { "family_name": "Barbastathis", "given_name": "George", "clpid": "Barbastathis-George" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" }, { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "Scherer", "given_name": "Axel", "clpid": "Scherer-A" }, { "family_name": "Koch", "given_name": "Christof", "orcid": "0000-0001-6482-8067", "clpid": "Koch-C" }, { "family_name": "Whitham", "given_name": "Gerald Beresford", "clpid": "Whitham-G-B" }, { "family_name": "Franklin", "given_name": "Joel N.", "clpid": "Franklin-J-N" }, { "family_name": "Perona", "given_name": "Pietro", "orcid": "0000-0002-7583-5809", "clpid": "Perona-P" }, { "family_name": "Andersen", "given_name": "Richard A.", "orcid": "0000-0002-7947-0472", "clpid": "Andersen-R-A" }, { "family_name": "Shimojo", "given_name": "Shinsuke", "orcid": "0000-0002-1290-5232", "clpid": "Shimojo-S" }, { "family_name": "Abu-Mostafa", "given_name": "Yaser S.", "clpid": "Abu-Mostafa-Y-S" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document.\r\n\r\nMemory is a key component of intelligence. In the human brain, physical structure and functionality jointly provide diverse memory modalities at multiple time scales. How could we engineer artificial memories with similar faculties? In this thesis, we attack both hardware and algorithmic aspects of this problem.\r\n\r\nA good part is devoted to holographic memory architectures, because they meet high capacity and parallelism requirements. We develop and fully characterize shift multiplexing, a novel storage method that simplifies disk head design for holographic disks. We develop and optimize the design of compact refreshable holographic random access memories, showing several ways that 1 Tbit can be stored holographically in volume less than 1 [...], with surface density more than 20 times higher than conventional silicon DRAM integrated circuits. To address the issue of photorefractive volatility, we further develop the two-lambda (dual wavelength) method for shift multiplexing, and combine electrical fixing with angle multiplexing to demonstrate 1,000 multiplexed fixed holograms. Finally, we propose a noise model and an information theoretic metric to optimize the imaging system of a holographic memory, in terms of storage density and error rate.\r\n\r\nMotivated by the problem of interfacing sensors and memories to a complex system with limited computational resources, we construct a computer game of Desert Survival, built as a high-dimensional non-stationary virtual environment in a competitive setting. The efficacy of episodic learning, implemented as a reinforced Nearest Neighbor scheme, and the probability of winning against a control opponent improve significantly by concentrating the algorithmic effort to the virtual desert neighborhood that emerges as most significant at any time. The generalized computational model combines the autonomous neural network and von Neumann paradigms through a compact, dynamic central representation, which contains the most salient features of the sensory inputs, fused with relevant recollections, reminiscent of the hypothesized cognitive function of awareness. The Declarative Memory is searched both by content and address, suggesting a holographic implementation. The proposed computer architecture may lead to a novel paradigm that solves \"hard\" cognitive problems at low cost.\r\n", "doi": "10.7907/1R63-9H50", "publication_date": "1998", "thesis_type": "phd", "thesis_year": "1998" }, { "id": "thesis:110", "collection": "thesis", "collection_id": "110", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-01102008-090916", "primary_object_url": { "basename": "Drolet_jjp_1997.pdf", "content": "final", "filesize": 10911191, "license": "other", "mime_type": "application/pdf", "url": "/110/1/Drolet_jjp_1997.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Optoelectronic devices for information storage and processing", "author": [ { "family_name": "Drolet", "given_name": "Jean-Jacques P.", "clpid": "Drolet-J-P" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Scherer", "given_name": "Axel", "clpid": "Scherer-A" } ], "thesis_committee": [ { "family_name": "Unknown", "given_name": "Unknown" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Optoelectronic information storage and processing systems offer many important advantages compared to their electronic and magnetic counterparts: speed, massive parallelism and insensitivity to interference. Optoelectronic devices are a pivotal technology in the implementation of such systems. Devices consisting of optical inputs and outputs and information processing circuits are needed to interface optoelectronic components and modules to electronic systems, and to perform operations that are more difficult to reliably implement using optics alone. The main thrust of our research is to develop and evaluate optoelectronic technologies conducive to highly integrated optoelectronic components and systems for cost-effective information storage and processing. \n\nAt the device level, we describe a simple and inexpensive method for fabricating liquid crystal modulators on silicon integrated circuits. The modulators provide analog amplitude or phase modulation at low voltages. They are compatible with mainstream very-large-scale-integration processes and require only a minimal amount of post-processing performed on conventionally fabricated die. Experimental data are presented and compared to theoretical predictions.\n\nAt the chip level, we present an innovative optoelectronic integrated circuit functioning as an optically or electrically addressed spatial light modulator. The device merges the functions of a spatial light modulator and a detector array in a holographic memory system. Moreover, it helps refresh dynamic holograms which slowly decay in a read/write photorefractive memory as a result of their exposure to the reference beam. When combined with the technique of conjugate readout, this device allows a lens-less data path and a very compact, self-aligning integration of the memory module. We also describe two neural arrays, using self-electro-optic-effect devices bonded to a silicon integrated circuit, and light-emitting diodes grown on a commercially processed gallium arsenide integrated circuit.\n\nFinally, at the system level, we describe several integrated system architectures for holographic information storage and processing based on conjugate readout and the aforementioned device. We formulate storage density and cost projections. We report on laboratory prototypes of integrated modular holographic memory. Dynamic holograms were sustained over 50 refresh/decay cycles. Experimental data is presented.\n", "doi": "10.7907/80x4-rf73", "publication_date": "1997", "thesis_type": "phd", "thesis_year": "1997" }, { "id": "thesis:1560", "collection": "thesis", "collection_id": "1560", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-05012006-124513", "primary_object_url": { "basename": "Luo_J_1996.pdf", "content": "final", "filesize": 11186591, "license": "other", "mime_type": "application/pdf", "url": "/1560/1/Luo_J_1996.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Monolithic GaAs VLSI optoelectronic neuron arrays", "author": [ { "family_name": "Luo", "given_name": "Jiafu", "clpid": "Luo-Jiafu" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" }, { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "Mead", "given_name": "Carver", "orcid": "0000-0003-4051-0462", "clpid": "Mead-C-A" }, { "family_name": "Corngold", "given_name": "Noel Robert", "clpid": "Corngold-N-R" }, { "family_name": "Nicolet", "given_name": "Marc-Aurele", "clpid": "Nicolet-M-A" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "This thesis focuses on the design and fabrication of GaAs monolithic optoelectronic integrated circuits (OEIC's) for use in optical neural networks. The basic circuit in a neuron array consists of GaAs MESFET (Metal-Semiconductor Field Effect Transistor) circuits and optical input/output (I/O) devices. By implementing the I/O process optically, we can greatly increase the neuron density for a 2-dimensional array and thus achieve highly parallel computation.\r\n\r\nBecause of the high loss involved in optical interconnections, high density neuron arrays require high gain photodetectors and high efficiency output devices. With responsivities up to 10(4)A/W and structure compatibility with MESFET circuits, optical FET detectors (OPFET's) are an excellent choice as photodetectors. Several techniques have been investigated in order to fabricate high efficiency LED's (light-emitting-diodes) at low current levels. Low power consumption neurons based on OPFET's and GaAs/A1GaAs double-Zn-diffusion double-heterojunction LED's are fabricated using in-house facilities.\r\n\r\nIndustrial foundries provide the most convenient answer to the challenge of fabricating high density 2-D neuron arrays. Two approaches will be described. The first approach utilizes the FET-SEED (self-electrooptic effect device) process from AT&T Bell labs. It provides monolithically integrated circuits with optical I/O devices and depletion mode FET's. In the other approach, GaAs/AlGaAs multiple quantum well modulators are grown on MOSIS GaAs MESFET circuits by MBE regrowth. It is found that in both approaches, the FET's can be used as high gain photodetectors even though the mechanisms are different, thus making it possible to achieve low power consumption high density neuron arrays. Various kinds of complex optoelectronic circuits can be fabricated through these two approaches.", "doi": "10.7907/F7DG-YM82", "publication_date": "1996", "thesis_type": "phd", "thesis_year": "1996" }, { "id": "thesis:4132", "collection": "thesis", "collection_id": "4132", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-10172005-155528", "primary_object_url": { "basename": "Curtis_kr_1994.pdf", "content": "final", "filesize": 9316869, "license": "other", "mime_type": "application/pdf", "url": "/4132/1/Curtis_kr_1994.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "3-D photopolymer disks for correlation and data storage, and cross-talk in volume holographic memories", "author": [ { "family_name": "Curtis", "given_name": "Kevin R.", "clpid": "Curtis-K-R" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "Grubbs", "given_name": "Robert H.", "clpid": "Grubbs-R-H" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "This thesis considers the optical storage and processing of data using volume holography. First, cross-talk noise due to geometrical considerations is calculated for volume holographic memories. Cross-talk is due to energy diffracted from non-Bragg matched gratings. The SNR (signal-to-noise-ratio) of holographic memories due to cross-talk noise is calculated for Fourier transform holograms stored by angle, wavelength, phase-coded, and rotational multiplexing methods. Considerations include page size, geometry, angular bandwidth of the optical system, wavelength of the light used, material size, spatial light modulator (SLM) contrast, and the phase of the image plane. The SNR for angle multiplexed image plane holograms is also calculated and compared to the results for Fourier transformed angle multiplexed holograms. A comparison of the various multiplexing methods based on cross-talk is presented, and then the effect of geometry and material dynamic range is included to determine when cross-talk will be the dominant noise source. The use of photopolymers as a holographic element is then presented. The recording characteristics of the DuPont photopolymer are described and a method of multiplexing multiple holograms in the photopolymer is given. A new method for multiplexing holograms (called peristrophic multiplexing) is described. This method significantly increases the storage capacity of thin films. After this, a 3-D disk-based correlator and storage device using the photopolymer is described and demonstrated. In this device, holograms are multiplexed at a given spot and then disk rotation/head motion are used to access multiple spots on the disk. Theoretical correlation speed, read-out rates, and the storage capacity of the 3-D disk as limited by geometry and laser power are given.\n", "doi": "10.7907/6FK7-Z369", "publication_date": "1994", "thesis_type": "phd", "thesis_year": "1994" }, { "id": "thesis:3039", "collection": "thesis", "collection_id": "3039", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-08072007-133843", "primary_object_url": { "basename": "Lin_sh_1992.pdf", "content": "final", "filesize": 10394982, "license": "other", "mime_type": "application/pdf", "url": "/3039/1/Lin_sh_1992.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "GaAs optoelectronic integrated circuits for optical neural network applications", "author": [ { "family_name": "Lin", "given_name": "Steven H.", "clpid": "Lin-S-H" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" }, { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Nicolet", "given_name": "Marc-Aurele", "clpid": "Nicolet-M-A" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Optoelectronic integrated circuits (OEIC's) have emerged as a viable method in the implementation of optical neurons required for a neural network. This is due to the increased capability in both the material and the device engineering in GaAs technology, which has proliferated incredibly fast during the last decade. In this thesis, two different approaches to monolithically integrate various electronic and optical devices are explored for the implementation of optical neurons. The first approach utilizes the technology from double heterojunction bipolar transistor for its potentially high current gain and its structural compatibility with optical devices. In achieving the current gain required for optical neurons, modeling of the base leakage current, effect of surface passivation and diffusion characteristics is performed for Zn-diffused bipolar transistors. The second approach employs metal semiconductor field-effect transistors as the driver for the optical devices. It is found that, by properly designing the circuit, high optical gain, low electrical power dissipation and low optical switching energy thresholding devices can be accomplished in this approach with large input-output isolation. Such performance is required if large arrays of optoelectronic neurons are to be inserted into a neural network to perform tasks that make neural computation a unique approach in solving a certain class of problems. In this thesis, an optical gain of 80 is demonstrated along with an electrical power dissipation of 1.6 mW and an optical switching energy of 10 pJ. These results generate high promises and optimism for the realization of a physical neural computer in the near future.", "doi": "10.7907/tqm4-en29", "publication_date": "1992", "thesis_type": "phd", "thesis_year": "1992" }, { "id": "thesis:2956", "collection": "thesis", "collection_id": "2956", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-07202007-143215", "primary_object_url": { "basename": "c_ji_1992.pdf", "content": "final", "filesize": 3934938, "license": "other", "mime_type": "application/pdf", "url": "/2956/1/c_ji_1992.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Generalization capability of neural networks", "author": [ { "family_name": "Ji", "given_name": "Chuanyi", "clpid": "Ji-Chuanyi" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Posner", "given_name": "Edward C.", "clpid": "Posner-E-C" }, { "family_name": "Abu-Mostafa", "given_name": "Yaser S.", "clpid": "Abu-Mostafa-Y-S" }, { "family_name": "Goodman", "given_name": "Rodney M.", "clpid": "Goodman-R-M" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The generalization capability of feedforward multilayer neural networks is investigated from two aspects: the theoretical aspect and the algorithmic aspect.
\r\n\r\nIn the theoretical part, a general relation is derived between the so-called VC-dimension and the statistical lower epsilon-capacity, and then applied to two cases. First, as a general constructive approach, it is used to evaluate a lower bound of the VC-dimension of two layer networks with binary weights and integer thresholds. Second, how the sample complexity may vary with respect to distributions is investigated through analyzing a particular network which separates two binary clusters. Bounds for the capacity of two layer networks with binary weights and integer thresholds are also obtained.
\r\n\r\nIn the algorithmic part, a network reduction algorithm is developed to study generalization in learning analog mappings. It is applied to control a two-link manipulator to draw characters. The network addition-deletion algorithm is described to find an appropriate network structure during learning. It is used to study the effect of sizes of networks on generalization, and applied to various classification problems including hand written digits recognition.
", "doi": "10.7907/HR3F-0410", "publication_date": "1992", "thesis_type": "phd", "thesis_year": "1992" }, { "id": "thesis:3173", "collection": "thesis", "collection_id": "3173", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-08202007-091426", "primary_object_url": { "basename": "Yamamura_aa_1992.pdf", "content": "final", "filesize": 15876466, "license": "other", "mime_type": "application/pdf", "url": "/3173/1/Yamamura_aa_1992.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Neural network control and an optoelectronic implementation of a multilayer feedforward neural network", "author": [ { "family_name": "Yamamura", "given_name": "Alan Akihiro", "clpid": "Yamamura-Alan-Akihiro" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Sideris", "given_name": "Athanasios", "clpid": "Sideris-A" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Artificial neural networks are a computational paradigm inspired by biological neural systems. By modeling neural networks to a certain degree after their counterparts in nature, it is hoped that they can capture those aspects of biological neural systems that allow them to outperform more conventional processing systems in tasks such as motor control and pattern recognition. A brief overview of neural networks is provided in Item 1, concentrating on those aspects pertinent to the remainder of this thesis.\r\n\r\nThe application of neural networks to control is examined in Item 2. A general control system can be divided into feedforward and feedback components. Specifically, the use of neural networks in learning to generate the feedforward control signal for unknown, potentially nonlinear, plants is examined. A class of learning algorithms applicable to feedforward networks is developed, and their use in learning to control a simulated two-link robotic manipulator is studied.\r\n\r\nAn optoelectronic implementation of a multilayer feedforward neural network, with binary weights and connections, is described in the final part of this thesis. The neurons and connections are implemented electronically on a custom VLSI chip. The pattern and strength of the connections is controlled, through photodetectors placed in the connections, by a pattern of light illuminating the chip. This pattern is read out, in parallel, from an optical disk. Issues concerning parallel readout of information from optical disks are discussed in Item 3, while Item 4 contains a descriptionn of both the design of the Optoelectronic Neural Network Chip (ONNC) and experiments involving the optical disk and neural network chip.\r\n", "doi": "10.7907/4dbn-z991", "publication_date": "1992", "thesis_type": "phd", "thesis_year": "1992" }, { "id": "thesis:2856", "collection": "thesis", "collection_id": "2856", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-07122007-073524", "primary_object_url": { "basename": "Neifeld_ma_1991.pdf", "content": "final", "filesize": 13772300, "license": "other", "mime_type": "application/pdf", "url": "/2856/1/Neifeld_ma_1991.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Optical memory disks in optical pattern recognition systems", "author": [ { "family_name": "Neifeld", "given_name": "Mark A.", "clpid": "Neifeld-M-A" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Unknown", "given_name": "Unknown" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "We describe the use of optical memory disks in optical pattern recognition systems. Algorithmic and architectural issues associated with the realization of such systems are discussed. Experimental demonstrations of several optical disk-based architectures are included to aid in the understanding of system limitations and performance issues. First we discuss correlation-based pattern recognition and describe the relationship between this approach and the neural paradigm. The need for invariances in image recognition leads to the notion of the reference image library. This approach is shown to be attractive in the case of limited processor and spatial light modulator dynamic range. We characterize the optical disk as a parallel readout device. An overview of optical storage media is included. Parallel readout of data from Sony sampled format media is characterized. We identify a match between the characteristics of the optical disk and the requirements for pattern recognition systems. Four optical disk-based image correlators which may serve as building blocks in disk-based pattern recognition systems are introduced. These image correlators are experimentally demonstrated and compared in terms of speed, efficiency, and sensitivity to noise sources and disk imperfections. We discuss advantages and limitations of these systems.\n\nWe include a discussion of learning and generalization in neural networks. We present a new learning algorithm and discuss its generalization characteristics. Three disk-based systems for pattern recognition are proposed. The first is a correlation-based architecture. The performance of this system as compared with theoretical expectations is encouraging; however, data rate constraints suggest the investigation of an alternate approach. The next two systems are more neurally inspired and realize the k-nearest neighbor and radial basis function algorithms. An evaluation of the performance of these two systems is presented with respect to the handwritten digit recognition problem.\n\nLastly, we present two candidates for future optoelectronic computing and pattern recognition systems. We detail the operation of these architectures and discuss the need for a better understanding of the relationship between mass memory and a general parallel processing environment.", "doi": "10.7907/5bbq-0q27", "publication_date": "1991", "thesis_type": "phd", "thesis_year": "1991" }, { "id": "thesis:2717", "collection": "thesis", "collection_id": "2717", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-06242005-160651", "primary_object_url": { "basename": "Hudson_rs_1991.pdf", "content": "final", "filesize": 12830404, "license": "other", "mime_type": "application/pdf", "url": "/2717/1/Hudson_rs_1991.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Radar imaging for aircraft identification and planetary astronomy", "author": [ { "family_name": "Hudson", "given_name": "Raymond Scott", "clpid": "Hudson-R-S" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Unknown", "given_name": "Unknown" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The potential for identifying aircraft using one-dimensional radar range profiles in conjunction with a bank of correlation filters is investigated. Filters which maximize the expected value of the correlation with a target's profiles are derived, and an algorithm for computing them is presented. The algorithm is used on an extensive set of real aircraft profiles, and target identification experiments are performed. It is found that an averaging of identifications of several profiles is required to achieve reliable identification.\n \nThe use of multiple radar range profiles to form two-dimensional images through the techniques of inverse synthetic aperture radar (ISAR) is explored. Particular attention is given to the blurring which can arise when the target aspect does not vary linearly with time. An iterative algorithm for estimating target motion is developed which allows well-focused images to be formed in these cases. It is applied to simulated data and to an acoustic imaging experiment.\n\nA technique for forming two-dimensional radar images of a spherical planetary surface using one-dimensional Doppler spectra is developed. Simulations are used to explore the technique's effectiveness and robustness. It is then applied to real data from Jupiter's moons Ganymede and Callisto, and to Mars.\n", "doi": "10.7907/cf3k-sv32", "publication_date": "1991", "thesis_type": "phd", "thesis_year": "1991" }, { "id": "thesis:1577", "collection": "thesis", "collection_id": "1577", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-05022006-155139", "type": "thesis", "title": "Photorefractive Volume Holography in Artificial Neural Networks", "author": [ { "family_name": "Brady", "given_name": "David Jones", "clpid": "Brady-David-Jones" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Bellan", "given_name": "Paul Murray", "clpid": "Bellan-P-M" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Kimble", "given_name": "H. Jeff", "clpid": "Kimble-H-J" }, { "family_name": "Hopfield", "given_name": "John J.", "clpid": "Hopfield-J-J" }, { "family_name": "Vahala", "given_name": "Kerry J.", "orcid": "0000-0003-1783-1380", "clpid": "Vahala-K-J" }, { "family_name": "Bellan", "given_name": "Paul Murray", "orcid": "0000-0002-0886-8782", "clpid": "Bellan-P-M" }, { "family_name": "Abu-Mostafa", "given_name": "Yaser S.", "clpid": "Abu-Mostafa-Y-S" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "This thesis describes the use of volume holography to implement large-scale linear transformations on distributed optical fields. Such transformations are useful in the construction of hardware for artificial neural networks. The reconstruction of multiple grating holograms in layers of thin transparencies and in continuous volume media is considered and conditions under which such holograms may be used for linear transformations are derived. The control of the nature of the transformation implemented using fractal sampling grids is reviewed and the impact of such sampling grids on the energy efficiency of the overall system is considered. Information storage in volume holograms is shown to require multiple exposures and the impact of multiple exposures on linear hologram formations in saturable media and photorefractive materials is considered. It is shown for both types of media that the overall diffraction efficiency of a recorded hologram must decrease with the square of the rank of the transformation implemented. A theory for hologram formation in photorefractive materials with multiple trapping species is developed and compared with experimental results. The impact of multiple species and fixing mechanisms on linear hologram formation is evaluated. A method for refreshing the diffraction efficiency of photorefractive holograms in adaptive systems is described and demonstrated. The construction of thick holograms for linear transformations in waveguides is considered. A novel method for controlling such holograms is described and demonstrated. Learning in holographic neural networks is considered and two experimental holographic neural systems are described. The relative strengths of optical and electronic technologies for implementations of neural interconnections are considered.
", "doi": "10.7907/1YB6-SE42", "publication_date": "1990", "thesis_type": "phd", "thesis_year": "1990" }, { "id": "thesis:2506", "collection": "thesis", "collection_id": "2506", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-06072007-105206", "primary_object_url": { "basename": "Gu_cxg_1990.pdf", "content": "final", "filesize": 17432688, "license": "other", "mime_type": "application/pdf", "url": "/2506/1/Gu_cxg_1990.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Optical Neural Networks Using Volume Holograms", "author": [ { "family_name": "Gu", "given_name": "Claire Xiang-Guang", "clpid": "Gu-Claire-Xiang-Guang" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Unknown", "given_name": "Unknown" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "The optical implementation of neural networks utilizing volume holograms is investigated. The intrinsic degeneracy effect that limits the number of independent interconnections are identified and analyzed by applying the K-space analysis. Basic relationships between the number of neurons, the number of interconnections and the size of the optical system that is used to implement the neural network are derived. Systematic methods for selecting the positions of the neurons to achieve the maximum number of independent interconnections are described. Experiments of global and local connectivities accomplished by using fractal sampling grids for eliminating the degenerate interconnections are presented. The degrees of freedom of the volume hologram and of the planar hologram are compared.", "doi": "10.7907/HW3F-PK12", "publication_date": "1990", "thesis_type": "phd", "thesis_year": "1990" }, { "id": "thesis:555", "collection": "thesis", "collection_id": "555", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-02082007-130728", "type": "thesis", "title": "Binary Correlators for Optical Computing and Pattern Recognition", "author": [ { "family_name": "Mok", "given_name": "Fai Ho", "clpid": "Mok-Fai-Ho" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Martel", "given_name": "Hardy Cross", "clpid": "Martel-H-C" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Goodman", "given_name": "Rodney M.", "clpid": "Goodman-R-M" }, { "family_name": "Hopfield", "given_name": "John J.", "clpid": "Hopfield-J-J" }, { "family_name": "Sideris", "given_name": "Athanasios", "clpid": "Sideris-A" }, { "family_name": "Abu-Mostafa", "given_name": "Yaser S.", "clpid": "Abu-Mostafa-Y-S" }, { "family_name": "Martel", "given_name": "Hardy Cross", "clpid": "Martel-H-C" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The matrix-vector multiplier is an important building block in optical information processing architectures, examples of which are correlators for pattern recognition, associative memories, and neural networks. Such architectures are most suitable for implementation by optics due to the ease in realizing dense interconnections optically. The success of the implementation partially relies on the quality of the SLM used to record the information for processing. Limited dynamic range for the representation of the data recorded is a common drawback suffered by most commercially available devices. In this thesis, the importance of the dynamic range of the device on the performance of the implementation is investigated. The effect of limited dynamic range on the signal to noise ratio, probability of error, capacity, and training of various forms of matrix-vector multipliers are addressed. Through the use of theoretical analyses, computer simulations, and optical experiments, it will be shown that a large dynamic range is not essential in most applications. Specifically, it is shown that only one bit of dynamic range, i.e. two gray levels, for the representation of each data point, results in acceptable loss in performance.
", "doi": "10.7907/dwpt-gn93", "publication_date": "1989", "thesis_type": "phd", "thesis_year": "1989" }, { "id": "thesis:443", "collection": "thesis", "collection_id": "443", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-02012007-140044", "type": "thesis", "title": "Optical Processing Using Photorefractive Crystals", "author": [ { "family_name": "Yu", "given_name": "Jeffrey Winston", "clpid": "Yu-Jeffrey-Winston" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" }, { "family_name": "Cohen", "given_name": "Donald S.", "clpid": "Cohen-D-S" }, { "family_name": "Vahala", "given_name": "Kerry J.", "clpid": "Vahala-K-J" }, { "family_name": "Breckinridge", "given_name": "James B.", "clpid": "Breckinridge-James-B" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The ability of photorefractive crystals to holographically record an optical image in real time allows one to use them in a variety of optical information processing systems. A number of such systems are presented in this thesis. To form the ground work used in analyzing the performance of photorefractive optical processors, a comparison between the Kukhtarev and Moharam models was done. The regimes where each model sufficiently predicted the response of the photorefractive crystal was determined. In addition, a new model based on a higher perturbation expansion of Kukhtarev's material equation is presented. This method allows one to numerically derive the profile of the space charge field recorded in the crystal and predict the regime where the Kukhtarev and Moharam models are most accurate.
\r\n\r\nThree optical processing systems are presented. The first, a photorefractive incoherent to coherent converter (PICOC), utilizes a photorefractive crystal as a spatial light modulator. Both the Kukhtarev and higher expansion models were used to analyze the performance of the converter. In the second example, the use of a photorefractive crystal as a time integrating detector is presented. By utilizing this crystal in an acousto-optic time integrating correlator, the output correlation is presented without the bias inherent in standard time integrating architectures. This allows one to utilize the full dynamic range of the output detector, thereby increasing the processing gain of the system. The third example utilizes a photorefractive crystal in a VanderLugt correlator. Standard VanderLugt correlators using planar holograms have been used successfully in pattern classification. In this thesis, we will derive the capacity of this system and demonstrate that by using a photorefractive crystal as the storage medium, the volume holographic properties of the crystal results in an increase in the capacity of the system. In addition, the angular selectivity of the crystal allows one to perform multi-category classification. The effect of using a volume hologram in a VanderLugt correlator is analyzed and experimental results presented.
", "doi": "10.7907/q49d-bb74", "publication_date": "1988", "thesis_type": "phd", "thesis_year": "1988" }, { "id": "thesis:2583", "collection": "thesis", "collection_id": "2583", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-06142006-094757", "primary_object_url": { "basename": "Hong_jh_1987.pdf", "content": "final", "filesize": 13705251, "license": "other", "mime_type": "application/pdf", "url": "/2583/1/Hong_jh_1987.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Optical Computing for Adaptive Signal Processing and Associative Memories", "author": [ { "family_name": "Hong", "given_name": "John Hyunchul", "clpid": "Hong-John-Hyunchul" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" }, { "family_name": "Abu-Mostafa", "given_name": "Yaser S.", "clpid": "Abu-Mostafa-Y-S" }, { "family_name": "Sideris", "given_name": "Athanasios", "clpid": "Sideris-A" }, { "family_name": "Koch", "given_name": "Christof", "orcid": "0000-0001-6482-8067", "clpid": "Koch-C" }, { "family_name": "Posner", "given_name": "Edward C.", "clpid": "Posner-E-C" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Optical techniques for performing two computing tasks are investigated. First, acousto-optical systems that implement adaptive filtering structures are presented for operation in environments that are not well characterized a priori or are time-varying. Theoretical analyses along with experimental confirmations are given to identify the important system parameters that affect the performance. Extensions of the systems to the multidimensional domain of phased array signal processing are discussed as well as novel implementations that use photorefractive crystals as time-integrating elements.
\r\n\r\nAlso investigated are various associative memory models. An acousto-optic implementation of the so-called Hopfield model is presented. The system's storage capacity and attraction radius are characterized experimentally and are shown to agree with computer simulations. Secondly, an upper bound is derived for the storage capacity of holographic associative memories that use planar holograms. It is shown that if the space bandwidth product of the hologram is N2, then the holographic memory can store at most N2/N3 associations, where N3 is the number of pixels in each output item. Finally, associative memories whose performance is invariant with respect to shifts in the input pattern position are considered. It is shown that nonlinear interconnections are required to achieve shift invariant operation, and optical implementations are discussed.
\r\n", "doi": "10.7907/3vpt-fn50", "publication_date": "1987", "thesis_type": "phd", "thesis_year": "1987" }, { "id": "thesis:1638", "collection": "thesis", "collection_id": "1638", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-05052006-155412", "type": "thesis", "title": "Time and Space Integrating Acousto-Optic Signal Processing", "author": [ { "family_name": "Wagner", "given_name": "Kelvin H.", "clpid": "Wagner-Kelvin-H" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" }, { "family_name": "Mead", "given_name": "Carver", "orcid": "0000-0003-4051-0462", "clpid": "Mead-C-A" }, { "family_name": "Abu-Mostafa", "given_name": "Yaser S.", "clpid": "Abu-Mostafa-Y-S" }, { "family_name": "Masson", "given_name": "Colin R.", "clpid": "Masson-Colin-R" }, { "family_name": "Lesh", "given_name": "James R.", "clpid": "Lesh-James-R" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "One dimensional acousto-optic signal processing techniques are examined from the systems and functional viewpoint, and are then used as building blocks to synthesize multidimensional time and space integrating architectures. Time and space integrating signal processing systems are capable of performing 2-dimensional linear transformations upon images or matrices, by sequentially entering rows of the image with a travelling wave acousto-optic Bragg cell. The travelling rows are frozen by a pulsed laser diode, and the stationary diffracted fields are spatially processed by an optical system. The successively transformed rows are sequentially multiplied by a time varying reference wavefront, and accumulated on a time integrating CCD detector array to complete the two dimensional processing. Long 1-dimensional signals can also be linearly transformed by a time and space integrating system, by using a similar strategy upon a folded, or rastered, version of the high time bandwidth product signal. Small pieces of the long signal are slid into the system with an acousto-optic devices, and are spatially transformed over the device aperture. Then, successively transformed portions of the long signal are multiplied by a reference, and appropriately delayed and accumulated on a 2-D CCD in order to perform multichannel time integrations in the orthogonal dimension. The desired high time bandwidth one dimensional linear transformation is represented in the folded coordinate space of the 2-dimensional output detector.
\r\n\r\nThe operational characteristics of the principal active devices used in these time and space integrating systems are examined from the viewpoint of the system architect. The effects of the devices on the overall system operation are discussed, and device designs intended for application in a time and space integrating system operating environment are proposed.
\r\n\r\nThe final chapter is a detailed theoretical and experimental investigation into the particular operating characteristics of systems designed to perform a folded spectrum analysis of very high time bandwidth signals. This spectrum analysis problem has a shift variant transformation kernel, which can be broken down into a succession of smaller temporal and spatial sub transformations. The 1-dimensional space integrating spectrum analysis operation performed by a lens is used to produce a coarse spectral channelization of the input signal, displayed as a one dimensional spatial profile. Each resolvable spectral channel is fine frequency analyzed by temporal integration, producing a resulting intensity variation of each channel in the orthogonal direction, thereby forming a folded representation of the desired high time bandwidth spectrum analysis. The information which is needed to perform the fine frequency analysis is carried on the optical phase, so interferometric techniques are employed in order to detect the phase and transform it to an optical intensity modulation. Various bias terms are produced on the detector by the interferometric detection operation, and techniques for removing the unwanted bias are investigated. These include spatial carrier encoding of the interferometric terms combined with bandpass filtering, and direct bias subtraction techniques.
", "doi": "10.7907/4WH0-H941", "publication_date": "1987", "thesis_type": "phd", "thesis_year": "1987" }, { "id": "thesis:883", "collection": "thesis", "collection_id": "883", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-03052008-095021", "type": "thesis", "title": "Linear Maps with Point Rules: Applications to Pattern Classification and Associative Memory", "author": [ { "family_name": "Venkatesh", "given_name": "Santosh Subramanyam", "clpid": "Venkatesh-Santosh-Subramanyam" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Posner", "given_name": "Edward C.", "clpid": "Posner-E-C" }, { "family_name": "McEliece", "given_name": "Robert J.", "clpid": "McEliece-R-J" }, { "family_name": "Abu-Mostafa", "given_name": "Yaser S.", "clpid": "Abu-Mostafa-Y-S" }, { "family_name": "Franklin", "given_name": "Joel N.", "clpid": "Franklin-J-N" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Generalisations of linear discriminant functions are introduced to tackle problems in pattern classification, and associative memory. The concept of a point rule is defined, and compositions of global linear maps with point rules are incorporated in two distinct structural forms\u2014feedforward and feedback\u2014to increase classification flexibility at low increased complexity. Three performance measures are utilised, and measures of consistency established.
\r\n\r\nFeedforward pattern classification systems based on multi-channel machines are introduced. The concept of independent channels is defined and used to generate independent features. The statistics of multi-channel classifiers are characterised, and specific applications of these structures are considered. It is demonstrated that image classification invariant to image rotation and shift is possible using multi-channel machines incorporating a square-law point rule. The general form of rotation invariant classifier is obtained. The existence of optimal solutions is demonstrated, and good sub-optimal systems are introduced, and characterised. Threshold point rules are utilised to generate a class of low-cost binary filters which yield excellent classification performance. Performance degradation is characterised as a function of statistical side-lobe fluctuations, finite system space-bandwidth, and noise.
\r\n\r\nSimplified neural network models are considered as feedback systems utilising a linear map and a threshold point rule. The efficacy of these models is determined for the associative storage and recall of memories. A precise definition of the associative storage capacity of these structures is provided. The capacity of these networks under various algorithms is rigourously derived, and optimal algorithms proposed. The ultimate storage capacity of neural networks is rigourously characterised. Extensions are considered incorporating higher-order networks yielding considerable increases in capacity.
", "doi": "10.7907/1YSB-Q028", "publication_date": "1987", "thesis_type": "phd", "thesis_year": "1987" }, { "id": "thesis:1020", "collection": "thesis", "collection_id": "1020", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-03192008-121641", "primary_object_url": { "basename": "Haney_mw_1986.pdf", "content": "final", "filesize": 15585280, "license": "other", "mime_type": "application/pdf", "url": "/1020/1/Haney_mw_1986.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Acousto-Optical Time-and-Space Integrating Processors for Real-Time Synthetic Aperture Radar Imaging", "author": [ { "family_name": "Haney", "given_name": "Michael William", "orcid": "0009-0001-8071-5561", "clpid": "Haney-Michael-William" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" }, { "family_name": "Elachi", "given_name": "Charles", "orcid": "009-0002-2156-967X", "clpid": "Elachi-C" }, { "family_name": "Masson", "given_name": "Colin R.", "clpid": "Masson-Colin-R" }, { "family_name": "Posner", "given_name": "Edward C.", "clpid": "Posner-E-C" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Vaidyanathan", "given_name": "P. P.", "orcid": "0000-0003-3003-7042", "clpid": "Vaidyanathan-P-P" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Acousto-optical processors for Synthetic Aperture Radar (SAR) imaging are presented. The new processors produce images at real-time rates by combining the operations of data collection, storage, and processing into a compact time-and-space integrating (TSI) architecture. In the TSI approach the 2-D SAR imaging problem is decomposed into a cascade of 2 distinct operations: a 1-D spatial integration of light for range compression, and a 1-D temporal integration of light for azimuth compression. These two operations are coupled via a common path interferometric scheme that is insensitive to mechanical vibrations.
\r\n\r\nThe results of an experimental characterization of the TSI approach, with simulated point scatterer radar echoes, are reported. The performance issues of interferometric bias removal, dynamic range, and resolution are addressed. The architecture is generalized to correct for range migration and the results of a range walk compensation experiment are presented. A programmable version of the TSI architecture, in which the fixed azimuth reference mask is replaced by an acousto-optic light modulator, is described. The application of the programmable architecture to both strip-map and spot-light mode SAR is analyzed and experimentally verified.
", "doi": "10.7907/64T4-7N83", "publication_date": "1986", "thesis_type": "phd", "thesis_year": "1986" }, { "id": "thesis:11461", "collection": "thesis", "collection_id": "11461", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:04152019-101001395", "type": "thesis", "title": "Optical Interactions in a Dielectric Material with Multiple Perturbations", "author": [ { "family_name": "Lee", "given_name": "Hyuk", "clpid": "Lee-Hyuk" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" }, { "family_name": "Papas", "given_name": "Charles Herach", "clpid": "Papas-C-H" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "Bellan", "given_name": "Paul Murray", "orcid": "0000-0002-0886-8782", "clpid": "Bellan-P-M" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The interaction of light propagating through a dielectric material with multiple perturbations is investigated.
\r\n\r\nA general coupled mode theory of two gratings is presented. The acousto-electro-optic effect is introduced as an example of an indirect interaction due to the acousto-optic and electro-optic effects. The acousto-electro-optic effect is analyzed using the general theory and is demonstrated experimentally. The application of this effect to light modulation and deflection is discussed in detail. Also a correlator that is based on the photorefractive acousto-electrooptic effect is demonstrated and analyzed theoretically.
", "doi": "10.7907/ek2w-4557", "publication_date": "1986", "thesis_type": "phd", "thesis_year": "1986" }, { "id": "thesis:1786", "collection": "thesis", "collection_id": "1786", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-05142003-111719", "type": "thesis", "title": "Complexity of Information Extraction", "author": [ { "family_name": "Abu-Mostafa", "given_name": "Yaser Said", "clpid": "Abu-Mostafa-Yaser-Said" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" }, { "family_name": "Kechris", "given_name": "Alexander S.", "orcid": "0000-0002-2226-0423", "clpid": "Kechris-A-S" }, { "family_name": "McEliece", "given_name": "Robert J.", "clpid": "McEliece-R-J" }, { "family_name": "Mead", "given_name": "Carver", "orcid": "0000-0003-4051-0462", "clpid": "Mead-C-A" }, { "family_name": "Posner", "given_name": "Edward C.", "clpid": "Posner-E-C" }, { "family_name": "Ryser", "given_name": "Herbert J.", "clpid": "Ryser-H-J" }, { "family_name": "Wilson", "given_name": "Richard M.", "clpid": "Wilson-R-M" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "This thesis describes a mathematical theory that interrelates the basic concepts of complexity, cost, information and reliability. The accessibility of information, as opposed to its availability, is characterized. Universal bounds for complexity distribution, implementation cost and decision reliability are estimated. These bounds give rise to a methodology for any consistent definition of a complexity measure. The basic notions of pattern recognition and information theory are directly related to computational complexity.
", "doi": "10.7907/FVKM-7J60", "publication_date": "1983", "thesis_type": "phd", "thesis_year": "1983" } ]