[ { "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: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" } ]