- 标题
- 摘要
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- 实验方案
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Direct Imaging of Isofrequency Contours of Guided Modes in Extremely Anisotropic All-Dielectric Metasurface
摘要： In this work, we investigate an all-dielectric metasurface based on the silicon on insulator platform for manipulating of guided modes in the visible and near-infrared spectral ranges. We use the Fourier modal method to demonstrate numerically, that guided modes excited in the metasurface support both hyperbolic-like and elliptic dispersion regimes. We implement a back focal plane microscope combined with a high refractive index solid immersion lens to directly image the isofrequency contours of the guided modes (surface waves). Reconstruction of dispersion unambiguously reveals the transition between different dispersion regimes.
关键词： Fourier microscopy,All-dielectric metasurface,isofrequency contours,Fourier modal method,dispersion reconstruction,surface waves
更新于2025-09-23 15:23:52
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Optimal High Efficiency 3D Plasmonic Metasurface Elements Revealed by Lazy Ants
摘要： Recent transmissive optical metamaterials that leverage a generalized form of Snell’s law to induce anomalous refraction of light have garnered considerable interest in both optical and materials communities. However, most of these designs have primarily centered around parametric studies of planar canonical structures for their low profile and relative ease of manufacturing. In many of these cases, all-dielectric designs are preferred over metallodielectrics due to their low loss characteristics. Moreover, considering modern advances in nanofabrication techniques, these canonical structures represent only a small portion of the design space that is explorable. In this work, we exploit a generalized Multi-Objective Lazy Ant Colony Optimization (MOLACO) algorithm and a modified Pareto locus search mechanism to optimize arbitrary three-dimensional meta-material unit cells in the optical regime based on the Membrane Projection Lithography technique. Our exploration has revealed unintuitive metallodielectric structures for phase-gradient metasurface applications in the mid-wave infrared (MWIR) regime that achieve transmission magnitudes comparable to the highest-performance all-dielectric designs found in the literature. As a proof-of-concept, a beam-steering metasurface is synthesized using these unintuitive unit cell geometries and is shown to achieve over 84% diffraction efficiency which is among the highest performing metallodielectric metasurfaces in the MWIR reported to date.
关键词： Three-Dimensional,Metallo-dielectric,Metasurface,Optimization,Inverse-Design
更新于2025-09-19 17:13:59
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Guided‐Mode Resonances in All‐Dielectric Terahertz Metasurfaces
摘要： Coupling of diffracted waves in gratings with the waveguide modes gives rise to the guided mode resonances (GMRs). The GMRs provide designer linewidth and resonance intensity amidst a broad background, and thus have been widely used for numerous applications in visible and infrared spectral regions. Here, terahertz GMRs are demonstrated in low-loss, all-dielectric metasurfaces, which are periodic square lattices of silicon cuboids on quartz substrates. The silicon cuboid lattice simultaneously acts as a diffraction grating and an in-plane slab waveguide, thereby resulting in the formation of terahertz GMRs. At oblique incidence, two distinct frequency detuned GMRs are observed. The frequency difference between these two GMRs increases at larger angle of incidence. However, extremely small angle of incidence causes destructive interference between these counter-propagating GMRs that leads to a nonradiative symmetry-protected bound state in the continuum. GMRs in all-dielectric silicon metasurfaces can have potential applications in the realization of efficient terahertz devices such as high-Q transmission filters with angular spectral selectivity, ultrafast modulators, and free-space couplers.
关键词： guided-mode resonance,bound states in the continuum,all-dielectric metasurface,terahertz
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE Photonics Conference (IPC) - San Antonio, TX, USA (2019.9.29-2019.10.3)] 2019 IEEE Photonics Conference (IPC) - All-Dielectric Metasurfaces: Optical Nonlinearities and Emission Control
摘要： In this work we show our results on the harmonic generation and nonlinear frequency mixing enhanced by Mie modes in GaAs metasurfaces. Moreover, we show enhancement and directionality control of the quantum dot emission embedded in the metasurface.
关键词： nonlinear frequency mixing,semiconductor metasurface,all-dielectric metasurface,second harmonic generation
更新于2025-09-12 10:27:22
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Simultaneous Spectral and Spatial Modulation for Color Printing and Holography Using All-Dielectric Metasurfaces
摘要： Metasurfaces possess the outstanding ability to tailor phase, amplitude and even spectral responses of light with an unprecedented ultrahigh resolution, thus have attracted significant interests. Here, we propose and experimentally demonstrate a novel meta-device that integrates color printing and computer-generated holograms within a single-layer dielectric metasurface by modulating spectral and spatial responses at subwavelength scale, simultaneously. In our design, such metasurface appears as a microscopic color image under white light illumination, while encrypting two different holographic images that can be projected at the far-field when illuminated with red and green laser beams. We choose amorphous silicon dimers and nanofins as building components, and use a modified parallel Gerchberg-Saxton algorithm to obtain multiple sub-holograms with arbitrary spatial shapes for image-indexed arrangements while avoiding the loss of phase information. Such a method can further extend the design freedom of metasurfaces. By exploiting spectral and spatial control at the level of individual pixels, multiple sets of independent information can be introduced into a single-layer device, the additional complexity and enlarged information capacity are promising for novel applications such as information security and anti-counterfeiting.
关键词： spectral and spatial modulation,color printing,meta-hologram,all-dielectric metasurface
更新于2025-09-12 10:27:22
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Ultra-Narrow Band Mid-Infrared Perfect Absorber Based on Hybrid Dielectric Metasurface
摘要： Mid-infrared perfect absorbers (PAs) based on metamaterials have many applications in material analysis and spectral detection thanks to the associated strong light–matter interaction. Most of the PAs are built as ‘metal nanostructure’-insulator-metals (MIM). In this paper, we propose an ultra-narrow band absorber based on dielectric metasurface with a metal film substrate. The absorptance comes from the plasmonic absorption in the metal film, where the absorption is enhanced (while the band of that is compressed) by the super cavity effect of the dielectric metasurface. Based on our numerical calculation, the full-width at half-maximum (FWHM) can reach 67 nm at 8 μm (8‰), which is more than two orders of magnitude smaller than the resonance wavelength and much narrower than the theoretical FWHMs of MIM absorbers. Moreover, we studied their application in infrared thermal imaging, which also has more benefits than MIM absorbers. This kind of hybrid dielectric metasurface provides a new route to achieve ultra-narrow band perfect absorbers in the mid-infrared regime and can be broadly applied in detectors, thermal emitters and bio-spectroscopy.
关键词： plasmonics,dielectric metasurface,mid-infrared,perfect absorber,sensing
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - All-Dielectric High-Q Metasurfaces for Infrared Absorption Spectroscopy Applications
摘要： The mid-infrared (mid-IR) spectral range is crucial for spectroscopic investigations of biological systems since it contains the characteristic absorption signatures (i.e., the molecular ‘fingerprints’) of chemical and biological analytes, which are uniquely determined by the vibrational modes and associated absorption bands of its chemical bonds. Here we present a novel nanophotonics-based approach for detecting molecular fingerprints, which utilizes imaging-based methods to provide spectrometer-less operation in a miniaturized sensor device ideally suited for analyzing complex biological systems. The central building block of this technique is a pixelated dielectric metasurface where the individual metapixels are engineered to provide sharp resonances at a given resonance frequency. Each metapixel is made out of specifically designed zig-zag resonator arrays, which employ the concept of bound states in continuum to create high-Q resonances. The detection performance of the experimentally realized metasurface sensor was demonstrated by interrogating a monolayer of recombinant protein A/G molecules, which reveals the characteristic amide I and amide II absorption bands as distinct regions with attenuated peak reflectance of the resonances. A comparison of the total reflectance signals of all the metapixels before and after material adsorption delivers a distinct barcode pattern which can be used for chemically specific molecule detection. Importantly, this molecular barcoding method operates under broadband illumination and detection conditions, meaning that the chemically specific signals can be obtained without the need for spectrometry.
关键词： high-Q resonances,dielectric metasurface,nanophotonics,molecular barcoding,mid-infrared,molecular fingerprints
更新于2025-09-11 14:15:04
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Nonlinear Holographic All-Dielectric Metasurfaces
摘要： Nonlinear holographic metasurfaces have been intensively studied due to their potentials in practical applications. So far, nonlinear holographic metasurfaces have only been realized with plasmonic nanoantennas, suffering from high absorption loss and low damage threshold. Herein we propose and experimentally demonstrate a novel mechanism for nonlinear holographic metasurfaces. In contrast to conventional studies, the all-dielectric metasurface is composed of C-shaped Si nanoantennas. The incident laser is enhanced by their fundamental resonance, whereas the generated third-harmonic generation (THG) signals are re-distributed to the air gap region via the higher-order resonance, significantly reducing the absorption loss at short wavelength and resulting in an enhancement factor as high as 230. After introducing abrupt phase changes from 0 to 2π to the C-elements, high-efficiency cyan and blue THG holograms have been experimentally generated with the Si metasurface for the very first time. This research shall shed light on the advances of nonlinear all-dielectric metasurfaces.
关键词： nonlinear hologram,metasurface,all-dielectric metasurface,higher-order resonance
更新于2025-09-09 09:28:46
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Information Encoding with Optical Dielectric Metasurface via Independent Multichannels
摘要： Information encryption and security is a prerequisite for information technology which can be realized by optical metasurface owing to its arbitrary manipulation over the wavelength, polarization, phase and amplitude of light. So far information encoding can be implemented by the metasurface in one-dimensional (1D) mode (either wavelength or polarization) only with several combinations of independent channels. Herein, we design dielectric metasurfaces by multiplexing for information encoding in a two-dimensional (2D) mode of both wavelength and polarization. 63 combinations made out of six independent channels by two circular polarization states (RCP and LCP) and three visible wavelengths (633 nm, 532 nm and 473 nm) are experimentally demonstrated, in sharp contrast with 7 combinations by 3 independent channels in 1D mode. This 2D mode encoding strategy enhances the encryption security dramatically and paves a novel pathway for escalating the security level of information in multichannel information encryption, anti-counterfeiting, optical data storage, and information processing.
关键词： Pancharatnam-Berry phase,photon spin-dependent state,multichannel,information processing,multiwavelength,dielectric metasurface
更新于2025-09-04 15:30:14