宽波段高吸收的多层齿轮形超材料吸收器设计

Design of Multi-Layer Gear-Shaped Metamaterial Absorber with Broadband and High Absorption

基于多尺度特征结构堆叠与法布里-珀罗共振原理,设计了一种宽波段高吸收的多层齿轮形超材料吸收器,该吸收器由两层不同尺度的介质-金属堆叠组成。采用时域有限差分方法分析其吸收特性,数值仿真结果表明,该吸收器在300~4000 nm的波长范围内的吸收率均在89%以上,平均吸收率可达94%,呈现一定的偏振不敏感特性,在60°大角度斜入射时,平均吸收率仍能保持93%。通过对谐振波长处的电磁场分布进行分析,可以得出,该吸收器的宽波段高吸收特性主要由法布里-珀罗共振、表面等离子体共振、局域表面等离子体共振以及多种共振相互间的杂化耦合作用决定。这种宽波段高吸收、大角度吸收、偏振不敏感的吸收器在光伏电池、隐形设备等领域具有潜在的应用价值。

A multi-layer gear-shaped metamaterial absorber with broadband and high absorption is designed based on multi-scale feature structure stacking and Fabry-Perot resonance theory.The absorber is composed of two layers of media-metal gear-shaped stacks with different sizes and the finite difference time domain method is used to analyze the absorption characteristics.Numerical results reveal that the absorptivity of this absorber in the 300-4000 nm band is above 89%,the average absorptivity can reach 94%,and the absorber shows certain polarization insensitivity.In addition,under 60°oblique incidence,it can still maintain an average absorbance of 93%.From the electromagnetic field distribution at the resonance wavelength,one can see that the broadband and high absorption characteristic of this absorber is mainly attributed to Fabry-Perot resonance,surface plasmon resonance,localized surface plasmon resonance as well as hybrid coupling among them.The proposed absorber has potential application value in photovoltaic cells,invisible devices,and other fields,due to broadband and high absorption,large-angle absorption,and polarization insensitivity.