检索结果-南通市图书馆

Wavefront-selective Fano resonant metasurfaces

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advanced Photonics 2021年第2期3卷 78-88页

作者： adam overvig Andrea Alù City University of New York Advanced Science Research CenterPhotonics InitiativeNew YorkUnited States City University of New York Graduate CenterPhysics ProgramNew YorkUnited States

Fano resonances are conventionally understood as sharp spectral features with selectivity in the momentum-frequency domain,implying that they can be excited only by plane waves with specific frequencies and incident *** demonstrate that Fano resonances can be made generally selective in the spacefrequency *** can be tailored to resonate only when excited by a frequency,polarization,and wavefront of *** generalization reveals that Fano systems are characterized by eigenwaves that scatter to their time-reversed image upon *** in conventional Fano systems this trivially occurs for normally incident plane waves,we show that,in general,the selected wavefront is locally retroreflected everywhere across the *** results show that conventional Fano resonances are a subset of a broader dichroic phenomenon with spin,spatial,and spectral *** demonstrate these concepts with nonlocal metasurfaces whose governing principles are deeply rooted in the symmetry features of quasi-bound states in the *** light–matter interactions and symmetry-protection make these phenomena uniquely suited for enriching applications in quantum optics,non-linear optics,augmented reality,and secure optical communications,laying the groundwork for a range of novel compact optical sources and devices.

关键词： nonlocal metasurface Fano resonance spatial selectivity quasi-bound states in the continuum

Broadband achromatic dielectric metalenses

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2018年第1期7卷 236-246页

作者： Sajan Shrestha adam C.overvig Ming Lu Aaron Stein Nanfang Yu Department of Applied Physics and Applied Mathematics Columbia UniversityNew YorkNY 10027USA Brookhaven National Laboratory Center for Functional NanomaterialsUptonNY 11973USA

Metasurfaces offer a unique platform to precisely control optical wavefronts and enable the realization of flat lenses,or metalenses,which have the potential to substantially reduce the size and complexity of imaging systems and to realize new imaging ***,it is a major challenge to create achromatic metalenses that produce a single focal length over a broad wavelength range because of the difficulty in simultaneously engineering phase profiles at distinct wavelengths on a single *** practical applications,there is a further challenge to create broadband achromatic metalenses that work in the transmission mode for incident light waves with any arbitrary polarization *** developed a design methodology and created libraries of meta-units—building blocks of metasurfaces—with complex cross-sectional geometries to provide diverse phase dispersions(phase as a function of wavelength),which is crucial for creating broadband achromatic *** elucidated the fundamental limitations of achromatic metalens performance by deriving mathematical equations that govern the tradeoffs between phase dispersion and achievable lens parameters,including the lens diameter,numerical aperture(NA),and bandwidth of achromatic *** experimentally demonstrated several dielectric achromatic metalenses reaching the fundamental *** metalenses work in the transmission mode with polarization-independent focusing efficiencies up to 50%and continuously provide a near-constant focal length over λ=1200–1650 *** unprecedented properties represent a major advance compared to the state of the art and a major step toward practical implementations of metalenses.

关键词： chromatic dielectric limitations

Dielectric metasurfaces for complete and independent control of the optical amplitude and phase

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Light(Science & Applications) 2019年第1期8卷 318-329页

作者： adam C.overvig Sajan Shrestha Stephanie C.Malek Ming Lu Aaron Stein Changxi Zheng Nanfang Yu Department of Applied Physics and Applied Mathematics Columbia UniversityNew YorkNY 10027USA Center for Functional Nanomaterials Brookhaven National LaboratoryUptonNY 11973USA Department of Computer Science Columbia UniversityNew YorkNY 10027USA

Metasurfaces are optically thin metamaterials that promise complete control of the wavefront of light but are primarily used to control only the phase of ***,we present an approach,simple in concept and in practice,that uses meta-atoms with a varying degree of form birefringence and rotation angles to create high-efficiency dielectric metasurfaces that control both the optical amplitude and phase at one or two *** opens up applications in computer-generated holography,allowing faithful reproduction of both the phase and amplitude of a target holographic scene without the iterative algorithms required in phase-only *** demonstrate all-dielectric metasurface holograms with independent and complete control of the amplitude and phase at up to two optical frequencies simultaneously to generate two-and three-dimensional holographic *** show that phaseamplitude metasurfaces enable a few features not attainable in phase-only holography;these include creating artifactfree two-dimensional holographic images,encoding phase and amplitude profiles separately at the object plane,encoding intensity profiles at the metasurface and object planes separately,and controlling the surface textures of three-dimensional holographic objects.

关键词： holographic phase complete

Multifunctional resonant wavefront-shaping meta-optics based on multilayer and multi-perturbation nonlocal metasurfaces

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Light(Science & Applications) 2022年第9期11卷 2194-2206页

作者： STEPHANIE CMALEK adam Covervig ANDREA ALÙ NANFANG YU Department of Applied Physics and Applied Mathematics Columbia UniversityNew YorkNY 10027USA Photonics Initiative Advanced Science Research CenterCity University of New YorkNew YorkNY 10031USA Physics Program Graduate CenterCity University of New YorkNew YorkNY 10016USA

Photonic devices rarely provide both elaborate spatial control and sharp spectral control over an incoming *** optical metasurfaces,for example,the localized modes of individual meta-units govern the wavefront shape over a broad bandwidth,while nonlocal lattice modes extended over many unit cells support high quality-factor ***,we experimentally demonstrate nonlocal dielectric metasurfaces in the near-infrared that offer both spatial and spectral control of light,realizing metalenses focusing light exclusively over a narrowband resonance while leaving off-resonant frequencies *** devices attain this functionality by supporting a quasi-bound state in the continuum encoded with a spatially varying geometric *** leverage this capability to experimentally realize a versatile platform for multispectral wavefront shaping where a stack of metasurfaces,each supporting multiple independently controlled quasi-bound states in the continuum,molds the optical wavefront distinctively at multiple wavelengths and yet stay transparent over the rest of the *** a platform is scalable to the visible for applications in augmented reality and transparent displays.

关键词： spectrum resonant supporting

Nanostructured fibers as a versatile photonic platform: radiative cooling and waveguiding through transverse Anderson localization

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Light(Science & Applications) 2018年第1期7卷 690-698页

作者： Norman Nan Shi Cheng-Chia Tsai Michael J.Carter Jyotirmoy Mandal adam C.overvig Matthew Y.Sfeir Ming Lu Catherine L.Craig Gary D.Bernard Yuan Yang Nanfang Yu Department of Applied Physics and Applied Mathematics Columbia UniversityNew YorkNY 10027USA Center for Functional Nanomaterials Brookhaven National LaboratoryUptonNY 11973USA Museum of Comparative Zoology Harvard UniversityCambridgeMA 02138USA Department of Electrical Engineering University of WashingtonSeattleWA 98195USA

Broadband high reflectance in nature is often the result of randomly,three-dimensionally structured *** study explores unique optical properties associated with one-dimensional nanostructures discovered in silk cocoon fibers of the comet moth,Argema *** fibers are populated with a high density of air voids randomly distributed across the fiber cross-section but are invariant along the *** filamentary air voids strongly scatter light in the solar spectrum.A single silk fiber measuring~50μm thick can reflect 66%of incoming solar radiation,and this,together with the fibers’high emissivity of 0.88 in the mid-infrared range,allows the cocoon to act as an efficient radiative-cooling *** inspiration from these natural radiative-cooling fibers,biomimetic nanostructured fibers based on both regenerated silk fibroin and polyvinylidene difluoride are fabricated through wet *** characterization shows that these fibers exhibit exceptional optical properties for radiative-cooling applications:nanostructured regenerated silk fibers provide a solar reflectivity of 0.73 and a thermal emissivity of 0.90,and nanostructured polyvinylidene difluoride fibers provide a solar reflectivity of 0.93 and a thermal emissivity of *** filamentary air voids lead to highly directional scattering,giving the fibers a highly reflective sheen,but more interestingly,they enable guided optical modes to propagate along the fibers through transverse Anderson *** discovery opens up the possibility of using wild silkmoth fibers as a biocompatible and bioresorbable material for optical signal and image transport.

关键词： fibers radiative transverse