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Electrical Control of Electromagnetically Induced Transparency by Terahertz Metamaterial Funneling
摘要： Electromagnetically induced transparency (EIT) analogs using metamaterials have diverse applications, including nonlinear optics, telecommunications, and biochemical sensors. These EIT analogs can be actively controlled by embedding semiconducting materials into metamaterial structures, but most active EIT metamaterials require complex optical setups and complicated fabrication processes. Graphene-based EIT metamaterials are some of the most promising active EIT systems because of their simple controllability by electrical bias, but related researches have so far been limited to theoretical or numerical studies. Here, experimentally verified graphene EIT metamaterials are provided by controlling the terahertz funneling of the unique metaatom structures. The proposed active EIT metamaterials are fabricated on flexible and ultrathin polyimide films to acquire the lowest substrate insertion losses and achieve a 1 ps group delay change at the transmission peak of the EIT analog. Moreover, because the proposed metamaterials exhibit resonance properties that vary depending on the polarization direction, the phase delay can be controlled up to 80° from the proposed metamaterials by rotating the incident polarization to the orthogonal direction. Overall, by controlling the group and phase delay of incident waves in a single metamaterial device simultaneously, a multifunctional active tuning system can be realized in the terahertz range.
关键词： terahertz,field enhancement,graphene,ion-gel,active metamaterials
更新于2025-09-10 09:29:36
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[Lecture Notes in Electrical Engineering] Advances in Signal Processing and Communication Volume 526 (Select Proceedings of ICSC 2018) || An Active Polarization-Insensitive Ultrathin Metamaterial Absorber with Frequency Controllability
摘要： In this paper, the design and simulated characteristics of the ultrathin square-shaped active metamaterial absorber are investigated. The unit cell of the proposed absorber is a fourfold symmetric structure consisting Jerusalem cross mounted with four pin diodes within the square ring. By switching the four diodes ON/OFF all at a time, the response of absorbance of this metamaterial structure switches from single-band to dual-band with polarization-insensitive characteristic.
关键词： FSS,Active,Absorber,Metamaterials,Polarization insensitive
更新于2025-09-10 09:29:36
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Plasmon Coupling Within the Multifold Nanorod Metasurface for Sensing Applications
摘要： A novel design for improving the sensing performance of localized surface plasmon resonance (LSPR) based nanosensors is proposed. We analyze the Fano-like coupling interaction within the multifold gold nanorod metasurface. By means of such Fano-like coupling effects, we can enhance the figure of merit (FoM) of nanosensors based on gold nanorod array by nearly one order. The main idea of our design can be easily adjusted for other nanophotonic platforms, and provides new possibilities for improving the performance of a myriad of applications, such as slow light devices, and optical switches.
关键词： metamaterials,Plasmonics,biosensors
更新于2025-09-10 09:29:36
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Graphene-over-graphite-based metamaterial structure as optical filter in the visible regime
摘要： Filtering aspects of graphene bilayer coated CYTOP glass substrate having the matrix of graphite embedded nanorods was touched upon. Transmission characteristics of the structure were analyzed taking into account different radii of graphite nanorods in the formation of substrate, the angle of incidence excitation, and also, the chemical potential of graphene. It was found that the structure exhibits high transmission and/or stop bands for certain range of frequencies under particular operating conditions. It is expected that such filters would find applications in notch and comb filtering.
关键词： complex mediums,engineered structures,Metamaterials,optical filters
更新于2025-09-10 09:29:36
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Regulation of Thermal Radiation Characteristics in Isotope Batteries Based on Fishnet Metamaterials
摘要： With space exploration, traditional photovoltaic cells are difficult to satisfy the needs of day and night alternation and deep space exploration. The development of isotope battery is becoming increasingly important. In this paper, a fishnet metamaterial is applied in the isotope battery to regulate the radiant energy of the heat source, achieving high transmission in the near-infrared bands and high reflection in the far-infrared band. The radiation process with spectral regulation is simulated by FLUENT commercial software. The results indicate that the temperature distribution of the isotope battery can be effectively changed by the spectral regulation of the fishnet metamaterial. The regulated radiant energy can increase the temperature of the heat source and reduce the temperature of the infrared photovoltaic cell. The results of this paper can provide potential application in the field of military and aerospace.
关键词： isotope battery,DO model,fishnet metamaterials
更新于2025-09-10 09:29:36
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Multipolar-interference-assisted terahertz waveplates via all-dielectric metamaterials
摘要： Polarization control via metamaterials boosts the design of polarimetric devices in the realm of terahertz technology for sensitive detection, bio-imaging, and wireless communication. Here, we propose all-dielectric metamaterials composed of silicon brick arrays that operate as terahertz quarter- and half-waveplates with close to unity transmission. Spherical multipole decomposition calculation indicates that the silicon brick can support multiple Mie-type resonances, such as electric dipole, electric quadrupole, magnetic dipole, and magnetic quadrupole modes. By tailoring the multipolar interference among these resonances, near unity transmission can be obtained with over p phase delay. We experimentally realize dielectric terahertz metamaterials that function as a quarter-wave plate at 0.79 THz and a half-wave plate at 0.91 THz with insertion losses of 0.54 and 1.25 dB, respectively. Such anisotropic dielectric metamaterials promise an exotic approach to engineer the interference among multipolar resonances and reveal the feasibility to realize functional, ef?cient, and compact terahertz meta-devices.
关键词： terahertz,waveplates,silicon brick arrays,all-dielectric metamaterials,multipolar interference
更新于2025-09-10 09:29:36
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Thermal meta-device in analogue of zero-index photonics
摘要： Inspired by the developments in photonic metamaterials, the concept of thermal metamaterials has promised new avenues for manipulating the flow of heat. In photonics, the existence of natural materials with both positive and negative permittivities has enabled the creation of metamaterials with a very wide range of effective parameters. In contrast, in conductive heat transfer, the available range of thermal conductivities in natural materials is far narrower, strongly restricting the effective parameters of thermal metamaterials and limiting possible applications in extreme environments. Here, we identify a rigorous correspondence between zero index in Maxwell’s equations and infinite thermal conductivity in Fourier’s law. We also propose a conductive system with an integrated convective element that creates an extreme effective thermal conductivity, and hence by correspondence a thermal analogue of photonic near-zero-index metamaterials, a class of metamaterials with crucial importance in controlling light. Synergizing the general properties of zero-index metamaterials and the specific diffusive nature of thermal conduction, we theoretically and experimentally demonstrate a thermal zero-index cloak. In contrast with conventional thermal cloaks, this meta-device can operate in a highly conductive background and the cloaked object preserves great sensitivity to external temperature changes. Our work demonstrates a thermal metamaterial which greatly enhances the capability for molding the flow of heat.
关键词： thermal cloak,zero-index photonics,thermal metamaterials,convective heat transfer,heat conduction
更新于2025-09-10 09:29:36
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Sub-wavelength focusing based on all-dielectric polarization-independent metalens
摘要： We have proposed an all-dielectric polarization-independent metalens, which can be used for sub-wavelength focusing. The phase discontinuity of transmission light is produced by varying the diameter of the nanopillar. In this way, the incident light can be focused into sub-wavelength spot. Besides, finite-difference time-domain results show that near diffraction limit focusing is realized for the wavelength from 580 nm to 750 nm, which means the proposed metalens possesses a broad operation bandwidth. This all-dielectric metalens features polarization independent and broad bandwidth, and thus promises great potential for the applications of nanolithography, dense storage and biophotonics.
关键词： metamaterials,Lenses,polarization
更新于2025-09-10 09:29:36
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Ultranarrow-band metagrating absorbers for sensing and modulation
摘要： Nanostructured plasmonic metamaterials are an excellent platform for narrowband optical absorption, which has wide applications in sensing, filtering, modulation, and emission tailoring. However, achieving a subnanometer absorption bandwidth for optical sensing and dynamical control of light is still challenging. Here, we propose an asymmetric metagrating structure and make use of the propagating surface plasmonic mode that has a small dissipation rate, to achieve perfect optical absorption with a bandwidth of 0.28 nm near the wavelength of 1.55 μm. Our proposed structure can be used in solution environments as a chemical or biological sensor in the visible spectral range just by changing the structural parameters. The sensor possesses a sensitivity of 440 nm/RIU and figure of merit of 1333.33 RIU?1. In addition, by combining an organic electro-optic material with this metagrating, our device can be reconfigurable with a dynamic range of 15.52 dB. Therefore, our proposed metagrating platform not only works as an ultranarrow-band absorber, but also can be employed for optical sensing and dynamic control of light.
关键词： sensing,optical absorption,metagrating,plasmonic metamaterials,modulation
更新于2025-09-10 09:29:36
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Surface enhanced perfect absorption in metamaterials with periodic dielectric nanostrips on silver film
摘要： Integrated dielectric metamaterials with plasmonic structures can cause drastic optical resonances and strengthen the capacity of light absorption. Here, we describe the optical properties of silicon nanoarrays on a thin silver film for extreme light confinement at subwavelength nanoscales. We attain the nearly total absorption in silicon nanostrips, which support magnetic quadruple Mie-type resonances in the visible regions. The Mie resonant field of the dielectric nanostrip engages the screening response of the silver film, resulting in plasmon resonance configuration and thus achieving perfect light absorption in the dielectric nanostrip. Moreover, we can attain similar results in other nanostructures, such as silicon cylinder and rhombus column arrays. Because it can sustain hybridized plasmon modes and magnetic modes, the combined system will benefit the application of solar energy accumulation.
关键词： surface plasmon polaritons,plasmonic structures,dielectric metamaterials,Mie resonances,perfect absorption
更新于2025-09-10 09:29:36