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Metasurfaces: Subwavelength nanostructure arrays for ultrathin flat optics and photonics
摘要： Miniaturization is a strong demand of modern scientific technology. However, conventional optical components based on refraction suffer from functional degradation as the device size decreases. Metasurfaces consisting of subwavelength optical antenna arrays have emerged as planar optical devices that enable many promising applications in lenses, holograms, and optical cloaks. During recent decades, metasurfaces have been developed for their specific functionalities by exploiting new materials and design algorithms. In this issue of MRS Bulletin, progress in metasurfaces is discussed to provide a comprehensive understanding of metasurfaces and their novel applications in optics and photonics.
关键词： subwavelength nanostructure arrays,photonics,Metasurfaces,ultrathin flat optics
更新于2025-09-23 15:19:57
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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) - Experimental Demonstration of Edge Detection by Dielectric Metasurfaces
摘要： Metasurfaces offer unique opportunities for optical signal processing and the design of neuromorphic optical networks for image-processing. Among different image-processing operations, edge detection is one of the essential algorithms with practical applications in microscopy or autonomous systems. The edge detection removes the plain parts of an image, to keep only the edges where the intensity changes abruptly. As such, the processed image contains just silhouettes of the object, Fig. 1a. In microscopy, edge detection helps to identify the structure of cells, while in autonomous systems, such as cars or drones, the optical edge detection can reduce the volume of data to compute on board of the vehicle, making it work faster and safer. To date, there have been several theoretical studies on metasurfaces for edge detection, however, an experimental demonstration is missing. Here we demonstrate experimentally edge detection by using the spatial dispersion of dielectric metasurfaces in the spectral vicinity of the Mie-type resonances (Fig. 1b). We show that a single ultra-thin (hundreds of nanometers) silicon metasurface can result in edge detection without any additional optical components and post computational processing.
关键词： Mie-type resonances,optical signal processing,dielectric metasurfaces,edge detection
更新于2025-09-23 15:19:57
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Lighta??Emitting Nanophotonic Designs Enabled by Ultrafast Laser Processing of Halide Perovskites
摘要： Nanophotonics based on resonant nanostructures and metasurfaces made of halide perovskites have become a prospective direction for efficient light manipulation at the subwavelength scale in advanced photonic designs. One of the main challenges in this field is the lack of large-scale low-cost technique for subwavelength perovskite structures fabrication preserving highly efficient luminescence. Here, unique properties of halide perovskites addressed to their extremely low thermal conductivity (lower than that of silica glass) and high defect tolerance to apply projection femtosecond laser lithography for nanofabrication with precise spatial control in all three dimensions preserving the material luminescence efficiency are employed. Namely, with CH3NH3PbI3 perovskite highly ordered nanoholes and nanostripes of width as small as 250 nm, metasurfaces with periods less than 400 nm, and nanowire lasers as thin as 500 nm, corresponding to the state-of-the-art in multistage expensive lithographical methods are created. Remarkable performance of the developed approach allows to demonstrate a number of advanced optical applications, including morphology-controlled photoluminescence yield, structural coloring, optical-information encryption, and lasing.
关键词： metasurfaces,structural coloration,lasing,halide perovskites,light emission,nanostructures
更新于2025-09-23 15:19:57
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Light Emission from Selfa??Assembled and Lasera??Crystallized Chalcogenide Metasurface
摘要： Subwavelength periodic confinement can collectively and selectively enhance local light intensity and enable control over the photoinduced phase transformations at the nanometer scale. Standard nanofabrication process can result in geometrical and compositional inhomogeneities in optical phase change materials, especially chalcogenides, as those materials exhibit poor chemical and thermal stability. Here the self-assembled planar chalcogenide nanostructured array is demonstrated with resonance-enhanced light emission to create an all-dielectric optical metasurface, by taking advantage of the fluid properties associated with solution-processed films. A patterned silicon membrane serves as a template for shaping the chalcogenide metasurface structure. Solution-processed arsenic sulfide metasurface structures are self-assembled in the suspended 250 nm silicon membrane templates. The periodic nanostructure dramatically manifests the local light–matter interaction such as absorption of incident photons, Raman emission, and photoluminescence. Also, the thermal distribution is modified by the boundaries and thus the photothermal crystallization process, leading to the formation of anisotropic nanoemitters within the field enhancement area. This hybrid structure shows wavelength-selective anisotropic photoluminescence, which is a characteristic behavior of the collective response of the resonant-guided modes in a periodic nanostructure. The resonance-enhanced Purcell effect can manifest the quantum efficiency of localized light emission.
关键词： optical antennas,laser processing,optical nanostructures,metasurfaces,Raman emission
更新于2025-09-23 15:19:57
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Simultaneous Fulla??Color Printing and Holography Enabled by Centimetera??Scale Plasmonic Metasurfaces
摘要： Optical metasurfaces enable novel ways to locally manipulate light’s amplitude, phase, and polarization, underpinning a newly viable technology for applications, such as high-density optical storage, holography, and displays. Here, a high-security-level platform enabled by centimeter-scale plasmonic metasurfaces with full-color, high-purity, and enhanced-information-capacity properties is proposed. Multiple types of independent information can be embedded into a single metamark using full parameters of light, including amplitude, phase, and polarization. Under incoherent white light, the metamark appears as a polarization- and angle-encoded full-color image with flexibly controlled hue, saturation, and brightness, while switching to multiwavelength holograms under coherent laser illumination. More importantly, for actual applications, the extremely shallow functional layer makes such centimeter-scale plasmonic metamarks suitable for cost-effective mass production processes. Considering these superior performances of the presented multifunctional plasmonic metasurfaces, this work may find wide applications in anticounterfeiting, information security, high-density optical storage, and so forth.
关键词： structural colors,plasmonics,metasurfaces,holograms
更新于2025-09-23 15:19:57
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Robustness of Optical Response for Selfa??Assembled Plasmonic Metamaterials with Morphological Disorder and Surface Roughness
摘要： Bottom-up fabrication of metallized biotemplated nanostructures to form specific plasmonic nanoresonators holds promise as a means of achieving large-scale optical metamaterials. However, in contrast to top-down methods, the stochastic growth of self-assembled nanoresonators is prone to significant disorder and surface roughness, which naturally raise an important question about the robustness of their resonant properties in terms of structural imperfections. An aggregated-random-sphere model is developed to mimic the nucleated growth of metallized DNA origami assembly, leading to meta-atoms with realistic, experimentally observed morphological disorder and surface roughness. Using the well-known split-ring-resonator (SRR) motif as an example, the resonant properties of meta-atoms under different levels of roughness are investigated and a strong tolerance of optical response against morphological disorder is revealed. It is found that in SRRs, even with dramatic roughness introduced, the expected resonances are still observed, despite broadening line shapes compared to ideal smooth structure. Only for extreme disorder, which causes drastic segmentation of SRRs, does the resonant response disappear. The demonstrations are very encouraging for the prospects of bottom-up fabrication toward versatile functional metamaterials and metadevices.
关键词： self-assembly,DNA origami,metamaterials,metasurfaces,surface roughness,morphological disorder
更新于2025-09-23 15:19:57
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2D Waveguided Bessel Beam Generated Using Integrated Metasurface-Based Plasmonic Axicon
摘要： Near-field imaging of the propagation of a diffraction-free Bessel-type beam in a guided wave configuration generated by means of a metasurface-based axicon lens integrated on a silicon waveguide is reported. The operation of the axicon lens with a footprint as small as 11μm2 is based on local engineering of the effective index of the silicon waveguide with plasmonic nanoresonators. This generic approach, which can be adapted to different types of planar lightwave circuit platforms, offers the possibility to design nano-engineered optical devices based on the use of plasmonic resonators to control light at the nanoscale.
关键词： Bessel beams,optical metasurfaces,Silicon photonics,surface plasmon resonances,Axicon
更新于2025-09-23 15:19:57
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Structural Colors Enabled by Lattice Resonance on Silicon Nitride Metasurfaces
摘要： Artificial color pixels based on dielectric Mie resonators are appealing for scientific research as well as practical design. Vivid colors are imperative for displays and imaging. Dielectric metasurface-based artificial pixels are promising candidates for developing flat, flexible, and/or wearable displays. Considering the application feasibility of artificial color pixels, wide color gamuts are crucial for contemporary display technology. To achieve a wide color gamut, ensuring the purity and efficiency of nanostructure resonance peaks in the visible spectrum is necessary for structural color design. Low-loss dielectric materials are suitable for achieving vivid colors with structural color pixels. However, high-order Mie resonances prevent color pixels based on dielectric metasurfaces from efficiently generating highly saturated colors. In particular, fundamental Mie resonances (electric/magnetic dipole) for red can result in not only a strong resonance peak at 650 nm, but also high-order Mie resonances at shorter wavelengths, which reduces the saturation of the target color. To address these problems, we fabricated silicon nitride metasurfaces on quartz substrates and applied Rayleigh anomalies at relatively short wavelengths to successfully suppress high-order Mie resonances, thus creating vivid color pixels. We performed numerical design, semianalytic considerations, and experimental proof-of-concept examinations to demonstrate the performance of the silicon nitride metasurfaces. Apart from traditional metasurface designs that involve transmission and reflection modes, we determined that lateral light incidence on silicon nitride metasurfaces can provide vivid colors through long-range dipole interactions; this can thus extend the applications of such surfaces to eyewear displays and guided-wave illumination techniques.
关键词： metasurfaces,Mie resonances,lattice resonances,color,silicon nitride,high-refractive-index nanostructures
更新于2025-09-23 15:19:57
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Programmable anisotropic digital metasurface for independent manipulation of dual-polarized THz waves based on a voltage-controlled phase transition of VO <sub/>2</sub> microwires
摘要： Programmable metasurfaces incorporated with tunable materials controlled by external stimuli can provide an unprecedented degree of freedom in dynamical wave manipulation in real-time. Beyond the scope of isotropic reconfigurable metasurfaces that only support unique tunable responses for excitation with a certain single-polarization, here, for the first time a new generation of ultrafast reprogrammable multi-functional anisotropic metasurface is reported to enable interchangeable missions independently for two orthogonal linearly polarized THz wavefront excitations. The reconfigurability of the proposed anisotropic meta-device was guaranteed by elaborately designed meta-particle composed of two perpendicular VO2 microwires whose operational statuses can be arbitrarily and dynamically tuned among two digital states of "0" and "1" independent for dual-polarization channels by mere changing the biasing voltage via two independent computer-programmed multichannel DC network. Capitalizing on such meta-particle design furnish an inspiring platform to manipulate the far-field scattering patterns and near-field behavior in each desired polarization channel. Anisotropic meta-device bringing new degrees of freedom in achieving versatile tunable control of differently polarized electromagnetic waves which will significantly enhance storage density and data capacities and has the potential for complicated wave manipulation such as ultrafast THz communication and dynamic holography.
关键词： anisotropic metasurface,wavefront engineering,VO2 microwires,THz waves,Programmable metasurfaces
更新于2025-09-23 15:19:57
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Self-Organized Conductive Gratings of Au Nanostripe Dimers Enable Tunable Plasmonic Activity
摘要： Plasmonic metasurfaces based on quasi-one-dimensional (1D) nanostripe arrays are homogeneously prepared over large-area substrates (cm2), exploiting a novel self-organized nanofabrication method. Glass templates are nanopatterned by ion beam-induced anisotropic nanoscale wrinkling, enabling the maskless con?nement of quasi-1D arrays of out-of-plane tilted gold nanostripes, behaving as transparent wire-grid polarizer nanoelectrodes. These templates enable the dichroic excitation of localized surface plasmon resonances, easily tunable over a broadband spectrum from the visible to the near- and mid-infrared, by tailoring the nanostripes’ shape and/or changing the illumination conditions. The controlled self-organized method allows the engineering of the nanoantennas’ morphology in the form of Au-SiO2-Au nanostripe dimers, which show hybridized plasmonic resonances with enhanced tunability. Under this condition, superior near-?eld ampli?cation is achievable for the excitation of the hybridized magnetic dipole mode, as pointed out by numerical simulations. The high e?ciency of these plasmonic nanoantennas, combined with the controlled tuning of the resonant response, opens a variety of applications for these cost-e?ective templates, ranging from biosensing and optical spectroscopies to high-resolution molecular imaging and nonlinear optics.
关键词： biosensing,plasmon hybridization,nanostripe dimers,self-organized nanoantennas,transparent nanoelectrodes,large-area metasurfaces,wire-grid polarizers
更新于2025-09-23 15:19:57