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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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Dual-wavelength plasmonic perfect absorber suitable for refractive index sensing
摘要： In this paper, a plasmonic perfect absorber (PPA) based on metal-insulator-metal-insulator-metal (MIMIM) structure has been designed for refractive index sensing of glucose solutions (analyte) and then a new method has been proposed for fast, low-cost, and easy measurement of sensor’s sensitivity. Simulation results show that the absorption spectrum of the proposed sensor has two resonance peaks that with an increase in analyte refractive index, both of them are red-shifted. In our proposed measurement technique, two conventional single-wavelength lasers (with wavelengths of 1050 nm and 1750 nm) are used for vertical plane wave light illumination on the structure. Then, the absorbed powers at 1750 nm (A2) and 1050 nm (A1) wavelengths are calculated and variation of the absorption ratio (A2/A1) due to change of analyte refractive index would be introduced as the sensitivity of sensor (S = Δ(A2/A1)/Δn). Obtained results show that the increase of analyte refractive index from n = 1.312 to n = 1.384 will result in an increase of sensor’s sensitivity from 9.3/RIU to 33.475/RIU.
关键词： A new definition of sensitivity,Absorption ratio,Plasmonic perfect absorber,Refractive index sensor
更新于2025-09-11 14:15:04
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Hybrid Metal-Semiconductor Meta-Surface Based Photo-Electronic Perfect Absorber
摘要： Metal films and semiconductor materials have been utilized for numerous optoelectronic devices due to the impressive electrical features. Nevertheless, the feasible way for achieving light anti-reflection or perfect absorption from opaque metal films and high-index semiconductors has not been established yet. In this work, we numerically propose and demonstrate a new functional metal-semiconductor slab, which can produce perfect light absorption in the optical range. High-index semiconductor resonators have been used to provide strong optical field coupling with the incident light. For the Ag-Si resonant slab consisting of a silicon rings array in the Ag slab, dual-band light absorption with the absorption efficiency above 99% is achieved due to the hybridized coupling of photonic and plasmonic modes for the Si and Ag resonators. Additionally, tri-band light absorption can be obtained when a paired silicon rings array is used. Moreover, these absorption properties can be spectrally manipulated via tuning the structural parameters. Furthermore, the absorber scheme is observed to be realizable by other metals and semiconductors. These optical and structural features can not only provide alternative ways for multi-band light absorption but also suggest new insight on the functional optoelectronics such as the infrared photo-detectors, hot-electron excitation and nonlinear optics.
关键词： meta-surface,plasmonic,hybrid metal-semiconductor,perfect absorber
更新于2025-09-11 14:15:04
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Transflective Mesoscopic Nanoparticles Synthesized in the Leidenfrost Droplet as Black Absorbers
摘要： Here, a new class of transflective oxide metaparticles that are able to capture solar radiation in a selective manner based on their size and morphology is demonstrated. The metaparticles possess an electronic polarization response “polarizonics” and show a specular reflective color at the visible frequencies. As a specific highlight, a resonating ultrathin reflective while transparent metacomposite, i.e., a transflective coating is designed. Further, a perfect solar absorber is devised whose function is morphology controlled and supplemented by the transflective coating via the selective interference concept. The multidisciplinary approach presented here enables design of materials with customized functionalities, bridging the sustainable nanochemistry to nanoengineering and proposes a new way for solving challenges in energy and solar harvesting.
关键词： perfect absorber,self-organization,the Leidenfrost chemistry,transflective coating,copper oxide
更新于2025-09-09 09:28:46
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Nonlinear coherent perfect photon absorber in asymmetrical atom–nanowires coupling system
摘要： Coherent perfect absorption provides a method of light-controlling-light and has practical applications in optical communications. Recently, a cavity-based nonlinear perfect photon absorption extends the coherent perfect absorber (CPA) beyond the linear regime. As nanowire-based system is a more competitive candidate for full-optical device, we introduce a nonlinear CPA in the single two-level atom–nanowires coupling system in this work. Nonlinear input–output relations are derived analytically, and three contributions of atomic saturation nonlinearity are explicit. The consociation of optical nonlinearity and destructive interference makes it feasible to fabricate a nonlinear monoatomic CPA. Our results also indicate that a nonlinear system may work linearly even when the incoming lights are not weak any more. Our findings show promising applications in full-optical devices.
关键词： single-atom system,nonlinear coherent perfect absorber,atom–nanowires coupling
更新于2025-09-09 09:28:46
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Recent Advances in Tunable and Reconfigurable Metamaterials
摘要： Metamaterials are composed of nanostructures, called artificial atoms, which can give metamaterials extraordinary properties that cannot be found in natural materials. The nanostructures themselves and their arrangements determine the metamaterials’ properties. However, a conventional metamaterial has fixed properties in general, which limit their use. Thus, real-world applications of metamaterials require the development of tunability. This paper reviews studies that realized tunable and reconfigurable metamaterials that are categorized by the mechanisms that cause the change: inducing temperature changes, illuminating light, inducing mechanical deformation, and applying electromagnetic fields. We then provide the advantages and disadvantages of each mechanism and explain the results or effects of tuning. We also introduce studies that overcome the disadvantages or strengthen the advantages of each classified tunable metamaterial.
关键词： plasmonics,metasurface,indium tin oxide,wavefront engineering,phase change material,color filter,perfect absorber,graphene
更新于2025-09-09 09:28:46
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Metasurface-Based THz Dual-Band Absorber Sensor for the Measurement of Refractive Index Variations of Chemical and Biological Substances
摘要： In this paper we report on the results of the simulations of the electromagnetic properties of a metasurface composed of a 2D-array of plasmonic nanoantennas acting as polarisation insensitive dual band THz perfect absorber able to achieve absorption coefficients and quality factors up to 99.6% and 122, respectively. The 2D-array is designed on top of a polyimide flexible film separating it from an Ag ground layer. The plasmonic nanoantenna is composed of two Ag quadrangular rings and an Ag diamond-shape dot is placed at their geometrical centre. The absorption resonances show a linear frequency shift with respect to variations of the refractive index of transparent substances adsorbed on the metasurface. This allows the dual-band absorber to be employed as a sensor of the chemical/physical modifications taking place on the substance. In particular, in terms of the refractive index units, the sensor based on the dual-band absorber can achieve sensitivities up to 310 GHz/RIU.
关键词： THz perfect absorber,functionalised metasurfaces,plasmonic sensors
更新于2025-09-09 09:28:46
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Tunable near-infrared perfect absorber based on the hybridization of phase-change material and nanocross-shaped resonators
摘要： Ge2Sb2Te5 (GST) is a kind of non-volatile chalcogenide phase-change material, which has a significant difference in permittivity between its amorphous and crystalline states in the infrared range. On account of this remarkable property, the combination of GST and metamaterials has great potential in tunable meta-devices. In this paper, a perfect absorber based on a nanocross-resonator array stacked above a GST spacer layer and an Au mirror (i.e., a metal-dielectric-metal configuration) is designed and experimentally demonstrated. A thin indium tin oxide (ITO) protective layer is inserted between the GST spacer and the Au resonator to avoid heat-induced oxidation of the GST layer during phase transition. We found that the ITO layer not only can protect the GST layer from deterioration, but also allows a significant blue shift in the absorption peak from 1.808 lm to 1.559 lm by optimizing the thickness of the two dielectric layers without scaling down the size of the metal structure, which provides a more feasible idea in pushing the absorption peak to higher frequency. The LC circuit model is presented to explain this blue-shift phenomenon, which is mainly attributed to the engineering of the dielectric environment of the parallel plate capacitance. In addition, such good performance in dynamitic modulation makes this perfect absorber a robust candidate for optical switching and modulating in various situations.
关键词： metamaterials,near-infrared,nanocross-shaped resonators,phase-change material,tunable,perfect absorber,GST
更新于2025-09-09 09:28:46
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Refractory Ultra-Broadband Perfect Absorber from Visible to Near-Infrared
摘要： The spectral range of solar radiation observed on the earth is approximately 295 to 2500 nm. How to widen the absorption band of the plasmonic absorber in this range has become a hot issue in recent years. In this paper, we propose a highly applicable refractory perfect absorber with an elliptical titanium nanodisk array based on a silica–titanium–silica–titanium four-layer structure. Through theoretical design and numerical demonstration, the interaction of surface plasmon resonance with the Fabry–Perot cavity resonance results in high absorption characteristics. Our investigations illustrate that it can achieve ultra-broadband absorption above 90% from a visible 550-nm wavelength to a near-infrared 2200-nm wavelength continuously. In particular, a continuous 712-nm broadband perfect absorption of up to 99% is achieved from wavelengths from 1013 to 1725 nm. The air mass 1.5 solar simulation from a ?nite-difference time domain demonstrates that this absorber can provide an average absorption rate of 93.26% from wavelengths of 295 to 2500 nm, which can absorb solar radiation ef?ciently on the earth. Because of the high melting point of Ti material and the symmetrical structure of this device, this perfect absorber has excellent thermal stability, polarization independence, and large incident-angle insensitivity. Hence, it can be used for solar cells, thermal emitters, and infrared detection with further investigation.
关键词： large incident-angle insensitivity,ultra-broadband,perfect absorber,refractory
更新于2025-09-04 15:30:14