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A Linear-to-Circular Polarization Conversion Metasurface Based Wideband Aperture Coupled Antenna
摘要： This paper proposes an aperture-coupled antenna with an ultrathin, single-layer metasurface for linear-to-circular (LP–CP) polarization conversion. The unit cell of the metasurface consists of a hexagonal ring surrounded by a square ring printed on both sides of a dielectric substrate for wideband LP-CP conversion. A patch antenna excited by an H-shaped slot aperture uses a 5 × 5 array of the metasurface as a superstrate. Simulated and measured radiation patterns of the proposed antenna are in good agreement. Measured S11 and axial ratio bandwidth of the proposed antenna are 21.5% and 19.23% respectively. Boresight radiation gain is around 10 dBic over 9.5 GHz to 11.5 GHz.
关键词： Circular polarization,Polarization conversion,Metasurface,Aperture coupled antenna,Wideband
更新于2025-09-23 15:19:57
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Broadband high-efficiency cross-polarization conversion and multi-functional wavefront manipulation based on chiral structure metasurface for terahertz wave
摘要： In this paper, a broadband and high-efficient tri-layered chiral structure metasurface (CSM) for linear polarization conversion and multi-functional wavefront manipulation was proposed and investigated numerically in terahertz region. The unit-cell of the proposed CSM consist of two orthogonal metal wires sandwiched with square split-ring resonator (SRR) structure, which can manipulate the polarization and wavefront of the transmitted wave simultaneously. Based on the Fabry-Perot-like cavity-enhanced effect of proposed CSM, broadband and high-efficiency cross-polarization conversion can be achieved. Numerical simulation results indicate that the cross-polarization transmission coefficient is higher than 0.9 from 0.4 THz to 1.0 THz, with a fractional bandwidth of 85.7%. The proposed CSM can achieve complete 2π phase coverage by adjusting the geometric parameters of the unit-cell structure. As a proof of multi-functional wavefront manipulation, anomalous refraction with a wide angle, two kinds of focusing metalenses and vortex beam generation are investigated to verify the multi-functional wavefront manipulation performance of the proposed CSM. Our work provides an effective method of enhancing the performance of transmission-type metasurface and the proposed devices show endless potential in wavefront control and communication applications in terahertz region.
关键词： chiral structure metasurface,linear polarization conversion,terahertz,wavefront manipulation
更新于2025-09-23 15:19:57
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Optoplasmonics: basic principles and applications
摘要： Plasmonic and photonic elements often have complementary optical properties, motivating the development of ‘optoplasmonic’ hybrid systems in which the photonic and plasmonic elements can synergistically interact. The overall goal in the design of optoplasmonic structures is to overcome the limitations of the individual building blocks or to generate entirely new properties that reach beyond what is possible with conventional photonic or plasmonic structures. After providing a brief introduction into the relevant optical properties of plasmonic and photonic building blocks, this manuscript reviews optoplasmonic architectures that contain plasmonic nanoantennas embedded in a de?ned photonic environment generated by discrete dielectric nanoparticles (NPs), microcavities, waveguides, or photonic crystals, as well as all-metal NP or metal/dielectric NP hybrid arrays in which diffracted modes interact with the plasmons of metal NPs. The fundamental working principles of these optoplasmonic systems are analyzed and selected applications and fabrication strategies are discussed.
关键词： metamaterials,metasurface,sensing,hybrid materials,high refractive index dielectrics,plasmonics,nanophotonics
更新于2025-09-23 15:19:57
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Polarization Multiplexing Terahertz Metasurfaces through Spatial Femtosecond Lasera??Shaping Fabrication
摘要： Terahertz (THz) metasurface has emerged as a powerful technique to fully modulate the wavefronts of THz radiation. To improve the information storage capability and enhance the encryption security of THz metasurface holograms, smart metasurface designs, and fabrications for polarization multiplexing are essential. In this study, two kinds of polarization multiplexing THz metasurfaces are fabricated through the slit-based spatial modulation of femtosecond laser. Controllable elliptical aperture arrays can easily and flexibly be fabricated on gold films by adjusting the width and position of the slit combined with the laser pulse energy. Based on the Pancharatnam–Berry phase and amplitude modulation, respectively, THz metasurfaces, with two independent target phases or amplitude profiles, are obtained. A variety of information can be processed under different polarization states through these THz metasurfaces. This method allows flexible and efficient customization of THz metasurfaces because of the high-speed fabrication and reproducibility as well as precise control of elliptical apertures location on the surface.
关键词： spatial shaping,THz metasurface,femtosecond laser fabrication,polarization multiplexing
更新于2025-09-23 15:19:57
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All-Dielectric Metasurface-Enabled Near-Infrared Switching Based on Ge2Sb2Te5 Phase-Change Material
摘要： A metasurface for use in multiscale applications in the near-infrared (NIR) range is proposed herein. A detailed study is carried out on a polarization-insensitive, single-layered, recon?gurable swastika-like metasurface for NIR switching. Using germanium antimony telluride (Ge2Sb2Te5) as a phase-change material, the metasurface works as a NIR switch in the wavelength range from 1.8 lm and 2.2 lm. The metasurface consists of a patterned Ge2Sb2Te5 thin ?lm on a glass substrate, making it an all-dielectric metastructure. A high switching contrast ratio, i.e., ratio of maximum to minimum transmission, of 150 was obtained. Light with different polarizations had no effect on the switching behavior of the metasurface, making it a potential candidate for the development of advanced, tunable, and integrated photonic devices.
关键词： optical switch,phase-change material,toroidal dipole resonances,Metasurface
更新于2025-09-23 15:19:57
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Chiral coding metasurfaces with integrated vanadium dioxide for thermo-optic modulation of terahertz waves
摘要： In the field of electromagnetics, there are many limitations to achieve simultaneous polarization conversion and wavefront control. The chiral coding metasurface based on the Pancharatnam-Berry (PeB) phase effectively helps to alleviate these restrictions and shows strong control over the terahertz radiation field. In this paper, the principle of chirality is theoretically analyzed and verified by simulation results. The circular dichroism DR (chiral effect) achieves 0.8. By combining the chirality and thermo-optic effect of vanadium dioxide (VO2), we propose three switchable metasurfaces for quantitative splitting and high-efficiency focusing (low-efficiency divergence) of terahertz beams. The amplitude switching efficiency of the circularly polarized (CP) and linearly polarized (LP) pencil beams is above 0.85. Under the excitation of LP waves, the first two chiral metasurfaces have one and two temperature-switchable reflective right-handed circularly polarized (RCP) pencil beams, respectively. The third chiral metasurface generates high-efficiency focusing for RCP waves and low-efficiency divergence for left-handed circularly polarized (LCP) waves. This work provides new methods for more flexible modulation of CP and LP waves and promotes the application of terahertz coding metasurfaces in communication.
关键词： Pancharatnam-Berry (PeB) phase,Vanadium dioxide,Thermo-optic effect,Chiral coding metasurface
更新于2025-09-23 15:19:57
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Active control of multiple, simultaneous nonlinear optical processes in plasmonic nanogap cavities
摘要： Plasmonic structures are promising to enhance and control nonlinear optical processes as the subwavelength-scale elements not only increase the local electric field intensities but also result in relaxed phase matching conditions. This opens the possibility to observe and further manipulate multiple nonlinear optical processes simultaneously which would be forbidden in bulk crystals due to incompatible phase matching requirements. Here we enhance and control the relative strength between third harmonic generation (THG), sum frequency generation (SFG) and four wave mixing (FWM) arising from 1-7 nm Al2O3 layers sandwiched between a gold film and silver nanorectangles. We demonstrate that the relative strength of the three, simultaneous nonlinear optical processes can be precisely controlled by either the ratio between the powers of the two excitations or the thickness of the Al2O3 layer. Furthermore, enhancements up to 106-fold for THG and FWM are observed along with 104-fold enhancements for SFG response when the resonance of the transverse and longitudinal mode of the cavity are matched to the two pump excitations. The ability to obtain and control multiple, nonlinear optical processes simultaneously opens new capabilities for advanced on-chip manipulation and processing of optical signals on the deep nanoscale.
关键词： metasurface,frequency conversion,plasmonics,tuning,nonlinear optics
更新于2025-09-23 15:19:57
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Non-resonant metal-oxide metasurfaces for efficient perovskite solar cells
摘要： The short-circuit current density and energy conversion efficiency of single-junction perovskite and perovskite/perovskite tandem solar cells can be increased by photon management. In this study, optical metasurfaces were investigated as potential light trapping structures oppose to commonly used pyramidal surface textures. Herein, metal oxide-based non-resonant metasurfaces were investigated as potential light-trapping structures in perovskite solar cells. The zinc oxide nanowire-based building blocks of the metasurface can be prepared by a templated electrodeposition through a mask of resist. The phase of the incident light can be controlled by the edge length of the subwavelength large zinc oxide nanowires. An array of zinc oxide nanowires was prepared and characterized in the current study. Three-dimensional (3D) finite-difference time-domain (FDTD) optical simulations were used to compare solar cells covered with non-resonant metasurfaces with commonly used light trapping structures. As compared to the solar cells covered with zinc oxide pyramid surface texture, solar cells with the integrated non-resonant metasurfaces exhibit almost identical quantum efficiencies and short-circuit current densities. Investigations of such metasurfaces will not only improve the photon absorption in perovskite solar cells but also reveal a pathway to make high-efficiency next-generation solar cells. Detailed guidelines for the realization of non-resonant metal oxide metasurfaces will be provided.
关键词： Light-trapping,Solar cell,Perovskite,Tandem,Metal oxides,Non-resonant metasurface
更新于2025-09-23 15:19:57
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Low-cost and high sensitivity glucose sandwich detection using a plasmonic nanodisk metasurface
摘要： Glucose detection using Surface-enhanced Raman scattering (SERS) spectroscopy has aroused considerable attention due to its potential in the prevention and diagnosis of diabetes as a result of its unique molecular fingerprinting capability, ultrahigh sensitivity and minimal interference from water. Despite numerous solutions to improve the sensitivity of glucose detection, the development of a new SERS-based strategy to detect glucose with high sensitivity and low-cost is still required. In this study, we propose a simple and sensitive SERS-based plasmonic metasurface sensing platform for a glucose sandwich assay using self-assembled p-mercapto-phenylboronic acid (PMBA) monolayers on a gold nanodisk (Au-ND) metasurface and synthesized silver nanoparticles (Ag NPs) modified with a mixture of p-aminothiophenol (PATP) and PMBA. The localized near-field of the proposed plasmonic metasurface is markedly enhanced due to the coupling between the Au-ND and Ag NPs, which greatly improves detection sensitivity. The experimental results show that SERS signals of the glucose assay are significantly enhanced by more than 8-fold, in comparison with the SERS substrate of smooth Au film and Ag NPs. Moreover, the plasmonic metasurface-based glucose sandwich assay exhibits high selectivity and sensitivity for glucose over fructose and galactose. The developed plasmonic metasurface sensing platform shows enormous potential for highly sensitive and selective SERS-based glucose detection and opens a new avenue for scalable and cost-effective biosensing applications in the future.
关键词： Surface-enhanced Raman scattering (SERS),glucose detection,gold nanodisk (Au-ND),p-mercapto-phenylboronic acid (PMBA),p-aminothiophenol (PATP),silver nanoparticles (Ag NPs),plasmonic metasurface
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