Centre for Optical and Electromagnetic Research, State Key Laboratory of Modern Optical Instrumentations, JORCEP (KTH-ZJU Joint Center of Photonics), Zhejiang University, Hangzhou 310058, China.
Nano Lett. 2012 Mar 14;12(3):1443-7. doi: 10.1021/nl204118h. Epub 2012 Feb 8.
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.
我们提出了一种由锯齿形各向异性超材料制成的超宽带薄膜红外吸收体。在很宽的频率范围内，在正常入射时的吸收率高于 95%，其中半最大值全吸收带宽约为 86%。这种特性在很宽的入射角范围内也能很好地保持。较短波长的光在较小宽度锯齿的上部被收集，而较长波长的光则被困在较大齿宽的下部。这种现象可以用各向异性超材料波导中的慢光模式来解释。我们的研究可以应用于设计光伏器件和热发射器的领域。
