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Mid- to long-wave infrared computational spectroscopy with a graphene metasurface modulator
摘要： In recent years there has been much interest concerning the development of modulators in the mid- to long-wave infrared, based on emerging materials such as graphene. these have been frequently pursued for optical communications, though also for other specialized applications such as infrared scene projectors. Here we investigate a new application for graphene modulators in the mid- to long-wave infrared. We demonstrate, for the first time, computational spectroscopy in the mid- to long-wave infrared using a graphene-based metasurface modulator. furthermore, our metasurface device operates at low gate voltage. to demonstrate computational spectroscopy, we provide our algorithm with the measured reflection spectra of the modulator at different gate voltages. We also provide it with the measured reflected light power as a function of the gate voltage. The algorithm then estimates the input spectrum. We show that the reconstructed spectrum is in good agreement with that measured directly by a fourier transform infrared spectrometer, with a normalized mean-absolute-error (nMAe) of 0.021.
关键词： metasurface,modulator,mid- to long-wave infrared,graphene,computational spectroscopy
更新于2025-09-23 15:21:01
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Ultrathin Circular Polarimeter Based on Chiral Plasmonic Metasurface and Monolayer MoSe2
摘要： Two-dimensional materials are ideal platforms for intriguing physics and optoelectronic applications because of their ultrathin thicknesses and excellent properties in optics and electronics. Further studies on enhancing the interaction between light and two-dimensional materials by combining metallic nanostructures have generated broad interests in recent years, such as enhanced photoluminescence, strong coupling and functional optoelectronics. In this work, an ultrathin circular polarimeter consisting of chiral plasmonic metasurface and monolayer semiconductor is proposed to detect light with different circular polarization within a compact device. A designed chiral plasmonic metasurface with sub-wavelength thickness is integrated with monolayer MoSe2, and the circular-polarization-dependent photocurrent responses of right and left circularly polarized light for both left- and right-handed metasurfaces are experimentally demonstrated. The photoresponse circular dichroism is also obtained, which further indicates the remarkable performance of the proposed device in detecting and distinguishing circularly polarized light. This design offers a great potential to realize multifunctional measurements in an ultrathin and ultracompact two-dimensional device for future integrated optics and optoelectronic applications with circularly polarized light.
关键词： circular polarimeter,chiral plasmonic metasurface,MoSe2,photocurrent responses,two-dimensional materials
更新于2025-09-23 15:21:01
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Narrowband, infrared absorbing metasurface using polystyrene thin films
摘要： We present the results of an experimental investigation of polystyrene’s suitability as a dielectric material for designing narrowband, infrared metasurface-based absorbers. Our study included characterization of processing parameters of polystyrene films, such as surface roughness and film thickness, which are critical for device fabrication, and the dielectric properties, which we measured, using spectroscopic ellipsometry. Our results confirm that thin film polystyrene is a relatively low-loss dielectric material at long-wave infrared (LWIR) frequencies. Subsequently, this material was used as the dielectric substrate of a thin, narrowband, metasurface-based absorber at LWIR frequencies. The fabricated narrowband absorber demonstrates excellent performance in the LWIR band with absorptivity as high as 96% and a full-width-at-half-maximum bandwidth of 0:502 μm or 4.87%.
关键词： metasurface,infrared,absorber,polystyrene,narrowband,LWIR
更新于2025-09-23 15:21:01
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Gray Level Image Encoding in Plasmonic Metasurfaces
摘要： Plasmonic metasurfaces have been widely used for image and color representation using nanoscale structures. By designing the size or shape of nanostructures, the phase or amplitude of transmitted or reflected electromagnetic spectrum can be manipulated via control of resonant wavelength, which results in multiple colors and can be used for color and/or image generation. Instead of color printing, we introduce a new approach from which images with multiple gray scales can be generated and hidden under light with specific wavelengths. In this work, plasmonic structures of nanorods with identical geometries are fabricated in arrays on a glass substrate, but the nanorods comprise binary alloys of aluminum and titanium; therefore, grayscale image information is encoded with the material composition. Under white light illumination with polarization along the long axis of a nanorod, the response of the nanorods has essentially the same resonant frequency, but with varying magnitudes of transmission. Based on this, using nanorods with four different compositions, four gray level imaging has been achieved. Since nanorods are sensitive to the polarization and spectral composition of the incident light, under unpolarized white light illumination, the image disappears. Therefore, this technique is promising in image encryption. We also show that the manipulation of light at the resonant wavelength by this method occurs in amplitude, not phase.
关键词： Image-encoding,Plasmonics,Metasurface
更新于2025-09-23 15:21:01
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A right-handed circularly polarized wave generated by a waveguide-fed holographic metasurface
摘要： We propose a novel method superposed two linearly polarized components to generate a right-handed circularly polarized (RCP) wave by using a holographic waveguide-fed metasurface. Combining with the holography principle and the polarizable particles based method, the expected RCP wave can be steered flexibly only by changing the slot state of each unit cell. A prototype generating a RCP wave at boresight direction is simulated, fabricated and measured, respectively. Both simulation and experiment results verify the good capability of the proposed metasurface. Applying this method, the resultant metasurface does not need a complex feeding network and can be easily extended to a reconfigurable CP metasurface. Therefore, the proposal has a huge potential in reconfigurable multifunctional CP devices.
关键词： waveguide-fed,metasurface,circularly polarized wave,holography
更新于2025-09-23 15:21:01
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Polarization selective metasurface formed by interference laser writing
摘要： Polarization dependent optical response of the periodically nanostructured SiO2-Ag nanocomposite material is investigated. As a result of the laser-based surface structuring, the reflection is found to be particularly enhanced and blueshifted for parallel polarisation. This result is attributed to the interaction between photonic and plasmonc resonances, namely to the coupling of the grating caused Rayleigh-Wood anomaly mode (described by using grating theory) with localized surface plasmon modes of the embedded Ag nanoparticles (described by using effective medium approach). The laser-induced formation of such metasurface allows precise control of the effect that is essential for practical application in photonics devices and optical filters.
关键词： photonic resonances,plasmonic resonances,polarization selective metasurface,interference laser writing,SiO2-Ag nanocomposite
更新于2025-09-23 15:21:01
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[IEEE 2019 International Symposium on Intelligent Signal Processing and Communication Systems (ISPACS) - Taipei, Taiwan (2019.12.3-2019.12.6)] 2019 International Symposium on Intelligent Signal Processing and Communication Systems (ISPACS) - Preliminary Design of a Waveguide-Fed Milimeter Wave Metasurface Antenna with LCD Controlled Array Factor for 5G User Equipment
摘要： The millimeter wave 5G communication promises wide bandwidth for high data rate throughput, however the available area on cellular user equipment (UE) is quite limited, and 2 dimensional phased array occupies a large area and is fairly complicated. In this article we explore the possibility a waveguide-fed millimeter wave metasurface antenna for 28 GHz band. The element is a generic T-metasurface, and LCD control of array factor is suggested with a glass lens to focus the beam. A fan shape beam is generated from this antenna with maximum gain around 16.7 dB. This design may serve the 5G mmW communication with simpler structure to nearby small cell station.
关键词： 5G,metasurface antenna,waveguide-fed,LCD control,millimeter wave
更新于2025-09-23 15:21:01
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TERAHERTZ BEAM SPLITTER BASED ON I-SHAPED METASURFACE
摘要： A linear polarization beam splitter operating in terahertz band is proposed and experimentally veri?ed in this paper. The unit cell of the beam splitter is composed of the top “I” type metal pattern, the middle dielectric layer, and the bottom metal layer. Each subarray structure of the device consists of four unit cells that rotate progressively at an angle of 45?. The horizontal and vertical sub-arrays form the gradient metasurface of 4 × 4. The incident linear polarized terahertz wave is re?ected by the device and divided into four beams with approximately equal power, while having di?erent propagating directions in the 0.18–0.30 THz band. The proposed terahertz beam splitter has the advantages of small size, low cost, and easy processing, and it can be applied to terahertz stealth and terahertz imaging.
关键词： terahertz,polarization,beam splitter,metasurface
更新于2025-09-23 15:21:01
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Multilayer Non-interacting Dielectric Metasurfaces For Multiwavelength Metaoptics
摘要： Metasurfaces provide a versatile platform for manipulating the wavefront of light using planar nanostructured surfaces. Transmissive metasurfaces, with full 2π phase control, are a particularly attractive platform for replacing conventional optical elements due to their small footprint and broad functionality. However, the operational bandwidth of metasurfaces has been a critical limitation and is directly connected to either their resonant response or the diffractive dispersion of their lattice. While multiwavelength and continuous band operation have been demonstrated, the elements suffer from either low efficiency, reduced imaging quality, or limited element size. Here, we propose a platform that provides for multiwavelength operation by employing tightly spaced multilayer dielectric metasurfaces. As a proof of concept, we demonstrate a multiwavelength metalens doublet (NA=0.42) with focusing efficiencies of 38% and 52% at wavelengths of 1180 nm and 1680 nm, respectively. We further show how this approach can be extended to three wavelength metalenses as well as a spectral splitter. This approach could find applications in fluorescent microscopy, digital imaging, and color routing.
关键词： Multiwavelength metalens,spectrum splitter,metasurface doublet,polarization-insensitive
更新于2025-09-23 15:21:01
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[IEEE 2018 11th UK-Europe-China Workshop on Millimeter Waves and Terahertz Technologies (UCMMT) - HangZhou, China (2018.9.5-2018.9.7)] 2018 11th UK-Europe-China Workshop on Millimeter Waves and Terahertz Technologies (UCMMT) - Single-Layer Dual-Band Anisotropic Coding Metasurface With Frequency- and Polarization-Dependent Properties
摘要： In this paper, a single-layer anisotropic coding metasurface is designed to work in dual-band, which has frequency- and polarization-dependent properties. By changing the frequency and polarization of the incident waves, the proposed single coding metasurface can achieve different electromagnetic (EM) functionalities independently. This design is experimentally demonstrated in the microwave frequency band and can be further exploited for realizing multifunctional devices.
关键词： Anisotropic,polarization-dependent,coding metasurface,dual-band
更新于2025-09-23 15:21:01