In this work,a simple fabrication method of germanium-based metasurfaces is proposed,where the deposited Al_(2)O_(3) layer with high selectivity is chosen as the hard mask and retained after the dry etching process.Th...In this work,a simple fabrication method of germanium-based metasurfaces is proposed,where the deposited Al_(2)O_(3) layer with high selectivity is chosen as the hard mask and retained after the dry etching process.The simulation and experimental characterization results verify the feasibility of the fabrication method.The experimental study on the fabrication methods of germanium-based metasurfaces is very significant as the meta-atoms with a higher refractive index can achieve 0 to 2πtransmission phase variation with a smaller period under the same thickness-to-period ratio,which is consistent with the requirement of the period miniaturization in some cases.展开更多
Transparent absorbers, with a functional integration of broadband electromagnetic shielding, microwave camouflage,and optical transparency, have attracted increasing attention in the past decades. Metal mesh, an artif...Transparent absorbers, with a functional integration of broadband electromagnetic shielding, microwave camouflage,and optical transparency, have attracted increasing attention in the past decades. Metal mesh, an artificial, optically transparent, conducting material composed of periodic metallic gratings, is the optimal choice for the microwave shielding layer of transparent absorbers because of its excellent compatibility between high transparency and low resistance. However, the micrometer-level periodicity of metallic grating concentrates the diffraction of light, which degrades the imaging quality of cameras and sensors in common. In this study, we report on a generalized Thiessenpolygon-randomization method that prevents the concentration of the diffraction of light in periodic metallic grating and demonstrate an ultrawide-band optically transparent diffraction-immune metamaterial absorber. The absorber is constructed with a multilayer indium-tin-oxide-based metasurface and a Thiessen-polygon-randomized metal-mesh reflector. The lossy metasurface provides multimode absorption, whereas the Thiessen-polygon randomization prevents the concentration of the diffraction of light. The practical sample achieves a 10 dB absorptivity and shielding effectiveness over a range of 8–26.5 GHz, and the optical transparency is also preserved over the entire visible and near-infrared regions. The point spread function and field of view are both improved by using the antidiffraction absorber. Our study paves the way for the application of optically transparent electromagnetic devices, display, and optoelectronic integration in a more practical stage. ? 2023 Chinese Laser Press.展开更多
基金supported by the National Natural Science Foundation of China(No.12204478).
文摘In this work,a simple fabrication method of germanium-based metasurfaces is proposed,where the deposited Al_(2)O_(3) layer with high selectivity is chosen as the hard mask and retained after the dry etching process.The simulation and experimental characterization results verify the feasibility of the fabrication method.The experimental study on the fabrication methods of germanium-based metasurfaces is very significant as the meta-atoms with a higher refractive index can achieve 0 to 2πtransmission phase variation with a smaller period under the same thickness-to-period ratio,which is consistent with the requirement of the period miniaturization in some cases.
基金National Natural Science Foundation of China (61901437, 62175083, 61935015)Fundamental Research Funds for the Central UniversitiesNatural Science Foundation of Jilin Province (20230101359JC)。
文摘Transparent absorbers, with a functional integration of broadband electromagnetic shielding, microwave camouflage,and optical transparency, have attracted increasing attention in the past decades. Metal mesh, an artificial, optically transparent, conducting material composed of periodic metallic gratings, is the optimal choice for the microwave shielding layer of transparent absorbers because of its excellent compatibility between high transparency and low resistance. However, the micrometer-level periodicity of metallic grating concentrates the diffraction of light, which degrades the imaging quality of cameras and sensors in common. In this study, we report on a generalized Thiessenpolygon-randomization method that prevents the concentration of the diffraction of light in periodic metallic grating and demonstrate an ultrawide-band optically transparent diffraction-immune metamaterial absorber. The absorber is constructed with a multilayer indium-tin-oxide-based metasurface and a Thiessen-polygon-randomized metal-mesh reflector. The lossy metasurface provides multimode absorption, whereas the Thiessen-polygon randomization prevents the concentration of the diffraction of light. The practical sample achieves a 10 dB absorptivity and shielding effectiveness over a range of 8–26.5 GHz, and the optical transparency is also preserved over the entire visible and near-infrared regions. The point spread function and field of view are both improved by using the antidiffraction absorber. Our study paves the way for the application of optically transparent electromagnetic devices, display, and optoelectronic integration in a more practical stage. ? 2023 Chinese Laser Press.
