[ { "id": "authors:tf4jq-e1862", "collection": "authors", "collection_id": "tf4jq-e1862", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200817-131929018", "type": "article", "title": "Perimeter-Control Architecture for Optical Phased Arrays and Metasurfaces", "author": [ { "family_name": "Davoyan", "given_name": "Artur", "orcid": "0000-0002-4662-1158", "clpid": "Davoyan-A-R" }, { "family_name": "Atwater", "given_name": "Harry", "orcid": "0000-0001-9435-0201", "clpid": "Atwater-H-A" } ], "abstract": "Tunable optical phased arrays and metasurfaces play an important role in a diverse range of applications from imaging and remote sensing to communications and displays. However, as the number of tunable elements grows, the required control architecture becomes insurmountably complex. Here, we discuss the concept of perimeter-controlled tuning to shape far-zone radiation. We discuss applications of our approach to beam forming, holography, and image projection. We show that, with a proper design, the complexity of a control architecture may be dramatically simplified. We further discuss the use of our method to time-sharing image projection and holography. Our concept is applicable to a variety of systems, including phased array optical antennas and metasurfaces.", "doi": "10.1103/physrevapplied.14.024038", "issn": "2331-7019", "publisher": "American Physical Society", "publication": "Physical Review Applied", "publication_date": "2020-08", "series_number": "2", "volume": "14", "issue": "2", "pages": "Art. No. 024038" }, { "id": "authors:taps6-g6e60", "collection": "authors", "collection_id": "taps6-g6e60", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200501-110449071", "type": "publication_deliverable", "title": "Direct Multipixel Imaging and Spectroscopy of an Exoplanet with a Solar Gravity Lens Mission", "author": [ { "family_name": "Turyshev", "given_name": "Slava G.", "clpid": "Turyshev-S-G" }, { "family_name": "Shao", "given_name": "Michael", "clpid": "Shao-Michael" }, { "family_name": "Toth", "given_name": "Viktor T.", "clpid": "Toth-V-T" }, { "family_name": "Friedman", "given_name": "Louis D.", "clpid": "Friedman-L-D" }, { "family_name": "Alkalai", "given_name": "Leon", "clpid": "Alkalai-L" }, { "family_name": "Mawet", "given_name": "Dimitri", "orcid": "0000-0002-8895-4735", "clpid": "Mawet-D" }, { "family_name": "Shen", "given_name": "Janice", "clpid": "Shen-Janice" }, { "family_name": "Swain", "given_name": "Mark R.", "orcid": "0000-0002-0919-4468", "clpid": "Swain-M-R" }, { "family_name": "Zhou", "given_name": "Hanying", "clpid": "Zhou-Hanying" }, { "family_name": "Helvajian", "given_name": "Henry", "clpid": "Helvajian-H" }, { "family_name": "Heinsheimer", "given_name": "Tom", "clpid": "Heinsheimer-T" }, { "family_name": "Janson", "given_name": "Siegfried", "clpid": "Janson-Siegfried" }, { "family_name": "Leszczynski", "given_name": "Zigmond", "clpid": "Leszczynski-Z" }, { "family_name": "McVey", "given_name": "John", "clpid": "McVey-John" }, { "family_name": "Garber", "given_name": "Darren", "clpid": "Garber-D" }, { "family_name": "Davoyan", "given_name": "Artur", "orcid": "0000-0002-4662-1158", "clpid": "Davoyan-A-R" }, { "family_name": "Redfield", "given_name": "Seth", "orcid": "0000-0003-3786-3486", "clpid": "Redfield-S" }, { "family_name": "Males", "given_name": "Jared R.", "clpid": "Males-J-R" } ], "abstract": "We examined the solar gravitational lens (SGL) as the means to produce direct high-resolution, multipixel images of exoplanets. The properties of the SGL are remarkable: it offers maximum light amplification of ~1e11 and angular resolution of ~1e-10 arcsec. A probe with a 1-m telescope in the SGL focal region can image an exoplanet at 30 pc with 10-kilometer resolution on its surface, sufficient to observe seasonal changes, oceans, continents, surface topography. We reached and exceeded all objectives set for our study: We developed a new wave-optical approach to study the imaging of exoplanets while treating them as extended, resolved, faint sources at large but finite distances. We properly accounted for the solar corona brightness. We developed deconvolution algorithms and demonstrated the feasibility of high-quality image reconstruction under realistic conditions. We have proven that multipixel imaging and spectroscopy of exoplanets with the SGL are feasible. We have developed a new mission concept that delivers an array of optical telescopes to the SGL focal region relying on three innovations: i) a new way to enable direct exoplanet imaging, ii) use of smallsats solar sails fast transit through the solar system and beyond, iii) an open architecture to take advantage of swarm technology. This approach enables entirely new missions, providing a great leap in capabilities for NASA and the greater aerospace community. Our results are encouraging as they lead to a realistic design for a mission that will be able to make direct resolved images of exoplanets in our stellar neighborhood. It could allow exploration of exoplanets relying on the SGL capabilities decades, if not centuries, earlier than possible with other extant technologies. The architecture and mission concepts for a mission to the strong interference region of the SGL are promising and should be explored further.", "doi": "10.48550/arXiv.2002.11871", "publisher": "arXiv", "publication_date": "2020-02-27" }, { "id": "authors:5em44-fge80", "collection": "authors", "collection_id": "5em44-fge80", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190110-124459264", "type": "article", "title": "Mimicking surface polaritons for unpolarized light with high-permittivity materials", "author": [ { "family_name": "Papadakis", "given_name": "Georgia T.", "orcid": "0000-0001-8107-9221", "clpid": "Papadakis-G-T" }, { "family_name": "Davoyan", "given_name": "Artur", "orcid": "0000-0002-4662-1158", "clpid": "Davoyan-A-R" }, { "family_name": "Yeh", "given_name": "Pochi", "clpid": "Yeh-Pochi" }, { "family_name": "Atwater", "given_name": "Harry A.", "orcid": "0000-0001-9435-0201", "clpid": "Atwater-H-A" } ], "abstract": "Tailoring near-field optical phenomena often requires excitation of surface plasmon polaritons (SPPs) or surface phonon polaritons (SPhPs), surface waves at the interface between media with electric permittivities of opposite sign. Despite their unprecedented field confinement, surface polaritons are limited by polarization: only transverse magnetic fields enable their excitation, leaving transverse electric fields unexploited. By contrast, guided modes in positive permittivity materials occur for both linear polarizations, however, they typically cannot compete with SPPs and SPhPs in terms of confinement. Here we show that omnipolarization guided modes in materials with high-permittivity resonances can reach confinement factors similar to SPPs and SPhPs, while surpassing them in terms of propagation distance. We explore the cases of silicon carbide and transition-metal dichalcogenides near their permittivity resonances, and compare with SPhPs in silicon carbide and SPPs in silver, at infrared and visible frequencies, respectively.", "doi": "10.1103/PhysRevMaterials.3.015202", "issn": "2475-9953", "publisher": "American Physical Society", "publication": "Physical Review Materials", "publication_date": "2019-01", "series_number": "1", "volume": "3", "issue": "1", "pages": "Art. No. 015202" }, { "id": "authors:h8w5p-j5d26", "collection": "authors", "collection_id": "h8w5p-j5d26", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180307-100751123", "type": "article", "title": "Materials challenges for the Starshot Lightsail", "author": [ { "family_name": "Atwater", "given_name": "Harry A.", "orcid": "0000-0001-9435-0201", "clpid": "Atwater-H-A" }, { "family_name": "Davoyan", "given_name": "Artur R.", "orcid": "0000-0002-4662-1158", "clpid": "Davoyan-A-R" }, { "family_name": "Ilic", "given_name": "Ognjen", "clpid": "Ilic-O" }, { "family_name": "Jariwala", "given_name": "Deep", "orcid": "0000-0002-3570-8768", "clpid": "Jariwala-D" }, { "family_name": "Sherrott", "given_name": "Michelle C.", "orcid": "0000-0002-7503-9714", "clpid": "Sherrott-M-C" }, { "family_name": "Went", "given_name": "Cora M.", "clpid": "Went-C-M" }, { "family_name": "Whitney", "given_name": "William S.", "orcid": "0000-0001-5269-2967", "clpid": "Whitney-W-S" }, { "family_name": "Wong", "given_name": "Joeson", "orcid": "0000-0002-6304-7602", "clpid": "Wong-Joeson" } ], "abstract": "The Starshot Breakthrough Initiative established in 2016 sets an audacious goal of sending a spacecraft beyond our Solar System to a neighbouring star within the next half-century. Its vision for an ultralight spacecraft that can be accelerated by laser radiation pressure from an Earth-based source to ~20% of the speed of light demands the use of materials with extreme properties. Here we examine stringent criteria for the lightsail design and discuss fundamental materials challenges. We predict that major research advances in photonic design and materials science will enable us to define the pathways needed to realize laser-driven lightsails.", "doi": "10.1038/s41563-018-0075-8", "issn": "1476-1122", "publisher": "Nature Publishing Group", "publication": "Nature Materials", "publication_date": "2018-10", "series_number": "10", "volume": "17", "issue": "10", "pages": "861-867" }, { "id": "authors:mefqk-g8c73", "collection": "authors", "collection_id": "mefqk-g8c73", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180606-104249888", "type": "article", "title": "Quantum nonlinear light emission in metamaterials: broadband Purcell enhancement of parametric downconversion", "author": [ { "family_name": "Davoyan", "given_name": "Artur", "orcid": "0000-0002-4662-1158", "clpid": "Davoyan-A-R" }, { "family_name": "Atwater", "given_name": "Harry", "orcid": "0000-0001-9435-0201", "clpid": "Atwater-H-A" } ], "abstract": "Single-photon and correlated two-photon sources are important elements for optical information systems. Nonlinear downconversion light sources are robust and stable emitters of single photons and entangled photon pairs. However, the rate of downconverted light emission, dictated by the properties of low-symmetry nonlinear crystals, is typically very small, leading to significant constraints in device design and integration. In this Letter, we study principles of spontaneous emission control (i.e., the Purcell effect) generalized to describe the enhancement of nonlinear generation of quantum light through spontaneous parametric downconversion. We develop a theoretical framework based on eigenmode analysis to study quantum nonlinear emission in a general anisotropic, dispersive, and lossy media. Our theory provides an unprecedented insight into the emission process. We find that spontaneous parametric downconversion in a media with hyperbolic dispersion is broadband and phase-mismatch-free. We further predict a significant enhancement of the downconverted emission rate in experimentally realistic nanostructures. Our theoretical formalism and approach to Purcell enhancement of nonlinear optical processes provides a framework for description of quantum nonlinear optical phenomena in complex nanophotonic structures.", "doi": "10.1364/OPTICA.5.000608", "issn": "2334-2536", "publisher": "Optical Society of America", "publication": "Optica", "publication_date": "2018-05-20", "series_number": "5", "volume": "5", "issue": "5", "pages": "608-611" }, { "id": "authors:ce6s2-dxb87", "collection": "authors", "collection_id": "ce6s2-dxb87", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20171025-101024290", "type": "article", "title": "Van der Waals Materials for Atomically-Thin Photovoltaics: Promise and Outlook", "author": [ { "family_name": "Jariwala", "given_name": "Deep", "orcid": "0000-0002-3570-8768", "clpid": "Jariwala-D" }, { "family_name": "Davoyan", "given_name": "Artur R.", "orcid": "0000-0002-4662-1158", "clpid": "Davoyan-A-R" }, { "family_name": "Wong", "given_name": "Joeson", "orcid": "0000-0002-6304-7602", "clpid": "Wong-Joeson" }, { "family_name": "Atwater", "given_name": "Harry A.", "orcid": "0000-0001-9435-0201", "clpid": "Atwater-H-A" } ], "abstract": "Two-dimensional (2D) semiconductors provide a unique opportunity for optoelectronics due to their layered atomic structure and electronic and optical properties. To date, a majority of the application-oriented research in this field has been focused on field-effect electronics as well as photodetectors and light emitting diodes. Here we present a perspective on the use of 2D semiconductors for photovoltaic applications. We discuss photonic device designs that enable light trapping in nanometer-thickness absorber layers, and we also outline schemes for efficient carrier transport and collection. We further provide theoretical estimates of efficiency indicating that 2D semiconductors can indeed be competitive with and complementary to conventional photovoltaics, based on favorable energy bandgap, absorption, external radiative efficiency, along with recent experimental demonstrations. Photonic and electronic design of 2D semiconductor photovoltaics represents a new direction for realizing ultrathin, efficient solar cells with applications ranging from conventional power generation to portable and ultralight solar power.", "doi": "10.1021/acsphotonics.7b01103", "issn": "2330-4022", "publisher": "American Chemical Society", "publication": "ACS Photonics", "publication_date": "2017-12-20", "series_number": "12", "volume": "4", "issue": "12", "pages": "2962-2970" }, { "id": "authors:k7mfq-hq430", "collection": "authors", "collection_id": "k7mfq-hq430", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180122-091821470", "type": "monograph", "title": "Purcell Enhancement of Parametric Luminescence: Bright and Broadband Nonlinear Light Emission in Metamaterials", "author": [ { "family_name": "Davoyan", "given_name": "Artur R.", "orcid": "0000-0002-4662-1158", "clpid": "Davoyan-A-R" }, { "family_name": "Atwater", "given_name": "Harry A.", "orcid": "0000-0001-9435-0201", "clpid": "Atwater-H-A" } ], "abstract": "Single-photon and correlated two-photon sources are important elements for optical information systems. Nonlinear downconversion light sources are robust and stable emitters of single photons and entangled photon pairs. However, the rate of downconverted light emission, dictated by the properties of low-symmetry nonlinear crystals, is typically very small, leading to significant constrains in device design and integration. In this paper, we show that the principles for spontaneous emission control (i.e. Purcell effect) of isolated emitters in nanoscale structures, such as metamaterials, can be generalized to describe the enhancement of nonlinear light generation processes such as parametric down conversion. We develop a novel theoretical framework for quantum nonlinear emission in a general anisotropic, dispersive and lossy media. We further find that spontaneous parametric downconversion in media with hyperbolic dispersion is broadband and phase-mismatch-free. We predict a 1000-fold enhancement of the downconverted emission rate with up to 105 photon pairs per second in experimentally realistic nanostructures. Our theoretical formalism and approach to Purcell enhancement of nonlinear optical processes, provides a framework for description of quantum nonlinear optical phenomena in complex nanophotonic structures.", "doi": "10.48550/arXiv.1709.07028", "publication_date": "2017-09-20" }, { "id": "authors:04jcv-db315", "collection": "authors", "collection_id": "04jcv-db315", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180420-112711469", "type": "book_section", "title": "Artificial magnetism in one-dimensional multilayer metamaterials", "book_title": "2017 Conference on Lasers and Electro-Optics (CLEO)", "author": [ { "family_name": "Papadakis", "given_name": "Georgia T.", "orcid": "0000-0001-8107-9221", "clpid": "Papadakis-G-T" }, { "family_name": "Fleischman", "given_name": "Dagny", "clpid": "Fleischman-D" }, { "family_name": "Davoyan", "given_name": "Artur", "orcid": "0000-0002-4662-1158", "clpid": "Davoyan-A-R" }, { "family_name": "Yeh", "given_name": "Pochi", "clpid": "Yeh-Pochi" }, { "family_name": "Atwater", "given_name": "Harry A.", "orcid": "0000-0001-9435-0201", "clpid": "Atwater-H-A" } ], "abstract": "Artificial magnetism is usually investigated in rather complex two- and three-dimensional metamaterials. We propose and experimentally demonstrate non-unity permeability in planar multilayer structures. We further demonstrate the existence of TE hyperbolic modes and magnetic plasmons.", "doi": "10.1364/CLEO_QELS.2017.FTh1G.5", "isbn": "978-1-9435-8027-9", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2017-05", "pages": "Art. No. FTh1G.5" }, { "id": "authors:8wwqd-tvb36", "collection": "authors", "collection_id": "8wwqd-tvb36", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170509-101657603", "type": "conference_item", "title": "Plasmon-Driven photoelectrochemical cells for artiftcial photosynthesis", "author": [ { "family_name": "Du Chene", "given_name": "Joseph S.", "orcid": "0000-0002-7145-323X", "clpid": "DuChene-J-S" }, { "family_name": "Tagliabue", "given_name": "Giulia", "orcid": "0000-0003-4587-728X", "clpid": "Tagliabue-G" }, { "family_name": "Welch", "given_name": "Alex J.", "orcid": "0000-0003-2132-9617", "clpid": "Welch-Alex-J" }, { "family_name": "Yang", "given_name": "Qin", "clpid": "Yang-Qin" }, { "family_name": "Reidy", "given_name": "Kate", "clpid": "Reidy-K" }, { "family_name": "Davoyan", "given_name": "Artur R.", "orcid": "0000-0002-4662-1158", "clpid": "Davoyan-A-R" }, { "family_name": "Hsiow", "given_name": "Chuen-Yo", "clpid": "Hsiow-Chuen-Yo" }, { "family_name": "Atwater", "given_name": "Harry", "orcid": "0000-0001-9435-0201", "clpid": "Atwater-H-A" } ], "abstract": "Artificial photosynthesis requires a material system that can harvest sunlight, carbon dioxide (CO_2), and water to produce chem. products (e.g. ethanol) in a solar-to-fuel process analogous to that employed by photosynthetic plants. Despite much promise, current CO_2-redn. catalysts require significant electrochem. overpotentials to achieve adequate activity while lacking appreciable chem. selectivity for a given product of interest. Numerous chem. compels. are often co-evolved during electrocatalytlc operation that are difficult to effectively sep. It is further noted that most catalysts operate under dark conditions through an applied elec. bias, but these reactions must ultimately be driven by excited-state carriers produced via light absorption to adequately mimic the photosynthetic machinery of natural systems. Plasmonic-metal nanostructures are promising candidates to drive photocatalytic CO_2 redn., as they possess broadly tunable optical properties coupled with catalytically active\nsurfaces for the prodn. of chem. fuels. In particular, the plasmon-mediated prodn. of energetic, so-called \"hot\" carriers on the metal nanostructure offers unique opportunities for plasmon-driven CO_2 redn. Tailoring the plasmon resonance energy with respect to the metal Fermi level provides a potential route to modify the hot carrier distributions for selectively initiating distinct\nphotochem. pathways on the metal surface with visible light. Although several plasmonic metals (e.g. Au and Cu) are known to exhibit electrocatalytic activity for CO_2 redn. under dark conditions, few examples of plasmon-driven photoelectrochem. cells for CO_2 redn. have been reported to date. Here, we detail our efforts related to the design and construction of plasmonic photoelectrodes for visible-light-driven CO_2 redn. in aq. soln. Various device architectures composed of meta/semiconductor heterostructures will be presented, including Au/GaN, Au/NiO, and Salisbury screen-type resonant absorbers exhibiting tunable absorption across the solar spectrum. Photoelectrochem. performance was correlated with the plasmon resonance of the device to evaluate the influence of plasmon excitation on Faradaic efficiency and product selectivity. The photocatalytic insights obtained from these studies are anticipated to inform the design of advanced plasmonic photosynthetic constructs for solar-to-fuel energy conversion.", "publisher": "Caltech Library", "publication_date": "2017-04" }, { "id": "authors:ppx46-c3w54", "collection": "authors", "collection_id": "ppx46-c3w54", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161107-092400775", "type": "monograph", "title": "Magnetism in one-dimensional metamaterials: Double hyperbolic media and magnetic surface states", "author": [ { "family_name": "Papadakis", "given_name": "Georgia T.", "orcid": "0000-0001-8107-9221", "clpid": "Papadakis-G-T" }, { "family_name": "Fleischman", "given_name": "Dagny", "clpid": "Fleischman-D" }, { "family_name": "Davoyan", "given_name": "Artur", "orcid": "0000-0002-4662-1158", "clpid": "Davoyan-A-R" }, { "family_name": "Yeh", "given_name": "Pochi", "clpid": "Yeh-Pochi" }, { "family_name": "Atwater", "given_name": "Harry A.", "orcid": "0000-0001-9435-0201", "clpid": "Atwater-H-A" } ], "abstract": "Metamaterials with magnetic properties have been widely investigated with rather complex two- and three-dimensional resonant structures. Here we propose conceptually and demonstrate experimentally a mechanism for broadband optical magnetism in simpler one-dimensional systems. We experimentally demonstrate that alternating high-index dielectric/metal multilayer hyperbolic metamaterials can exhibit a strong magnetic response including variously \u00b5>1 to \u00b5<0. By engineering the electric permittivity as well, we reveal an epsilon and mu near zero regime. We show that modifications of internal metamaterial structure can lead to either type I or type II magnetic hyperbolic dispersion, thereby generalizing the notion of a hyperbolic metamaterial to encompass both TE and TM polarizations in simple multilayer geometries. Finally, we show that a negative magnetic response can give rise to TE interface-bound states, analogous to their TM counterparts, surface plasmon polaritons.", "doi": "10.48550/arXiv.1608.02909", "publication_date": "2016-08-09" }, { "id": "authors:7tj7n-9m246", "collection": "authors", "collection_id": "7tj7n-9m246", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170111-123415340", "type": "book_section", "title": "Tailoring Spontaneous Parametric Downconversion in Hyperbolic Metamaterials", "book_title": "Conference on Lasers and Electro-Optics (CLEO) 2016", "author": [ { "family_name": "Davoyan", "given_name": "Artur R.", "orcid": "0000-0002-4662-1158", "clpid": "Davoyan-A-R" }, { "family_name": "Atwater", "given_name": "Harry A.", "orcid": "0000-0001-9435-0201", "clpid": "Atwater-H-A" } ], "abstract": "We study theoretically spontaneous parametric downconversion in nonlinear hyperbolic metamaterials and reveal that a strong enhancement of downconverted photon generation is possible due to the hyperbolic dispersion and modified optical density of states.", "doi": "10.1364/CLEO_QELS.2016.FW1B.2", "isbn": "978-1-943580-11-8", "publisher": "Optical Society of America", "place_of_publication": "Washington, DC", "publication_date": "2016-06", "pages": "Art. No. FW1B.2" } ]