Chen Sai, Chen Zhao, Liu Junku, Cheng Jierong, Zhou Yi, Xiao Lin, Chen Kai
Nanophotonics and Optoelectronics Research Center, Qian Xuesen Laboratory of Space Technology, China Academy of Space Technology, Beijing 100094, China.
Institute of Modern Optics, Nankai University, Tianjin 300350, China.
Nanomaterials (Basel). 2019 Sep 20;9(10):1350. doi: 10.3390/nano9101350.
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.
基于超材料的中红外完美吸收体（PAs）由于其相关的强光与物质相互作用，在材料分析和光谱检测中有许多应用。大多数完美吸收体被构建为“金属纳米结构”-绝缘体-金属（MIM）结构。在本文中，我们提出了一种基于带有金属薄膜衬底的介质超表面的超窄带吸收体。吸收率来自金属薄膜中的等离子体吸收，其中通过介质超表面的超腔效应，吸收得到增强（同时其带宽被压缩）。基于我们的数值计算，在8μm（8‱）处半高宽（FWHM）可达到67nm，这比共振波长小两个数量级以上，并且比MIM吸收体的理论半高宽窄得多。此外，我们研究了它们在红外热成像中的应用，这也比MIM吸收体有更多优势。这种混合介质超表面为在中红外波段实现超窄带完美吸收体提供了一条新途径，并且可以广泛应用于探测器、热发射器和生物光谱学中。
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