Ultrabroadband Light Absorption by a Sawtooth Anisotropic Metamaterial Slab

作者：Yanxia Cui, Kin Hung Fung, Jun Xu, Hyungjin Ma, Yi Jin, Sailing He, Nicholas X. Fang · 发表于：Nano Letters · 年份：2012 · DOI：10.1021/nl204118h · 被引用次数：1014 · 研究领域：Metamaterials and Metasurfaces Applications、Advanced Antenna and Metasurface Technologies、Plasmonic and Surface Plasmon Research

We present an ultrabroadband thin-film infrared absorber made of sawtoothed anisotropic metamaterial. Absorptivity of higher than 95% at normal incidence is supported in a wide range of frequencies, where the full absorption width at half-maximum is about 86%. Such property is retained well at a very wide range of incident angles too. Light of shorter wavelengths are harvested at upper parts of the sawteeth of smaller widths, while light of longer wavelengths are trapped at lower parts of larger tooth widths. This phenomenon is explained by the slowlight modes in anisotropic metamaterial waveguide. Our study can be applied in the field of designing photovoltaic devices and thermal emitters.