基于圆形简单微纳结构的长波红外吸收器设计

Design of long-wave infrared absorber based on circular simple micro-nano structure

超材料可以通过表面等离激元调控光的振幅、相位等特性,实现光的近场增强。通过改变材料的结构单元、排列方式等,可以设计材料的电磁参量,从而提高吸收率.基于表面等离激元谐振的电磁响应特性以及吸收光的机制,选择金属-介质-金属的3层结构设计了圆盘和环形微纳结构谐振吸收器.通过优化圆盘谐振吸收器的半径和介质层的厚度,在8~14μm的最高平均吸收率达到91.41%;通过优化环形谐振吸收器的内外半径和介质层的厚度,在8~14μm的平均吸收率达到93.33%.实验结果表明:设计的圆盘和环形谐振吸收器8~14μm的红外波段实现近完美的光吸收,不同的入射光波长可以激发传播型表面等离激元或者局域等离激元谐振.

Metamaterials can modulate the amplitude,phase and other properties of light through the mechanism of surface plasmons to achieve near-field enhancement of light.By changing the structural unit and arrangement of the material,the electromagnetic parameters of the material can be designed to improve the absorption.The three-layer structure of metal-medium-metal was picked out to design the circular and annular micro-nano structure resonant absorbers based on the electromagnetic response characteristics of the surface equipartition excitations and the absorption mechanism.Various optimizations of the radius and thickness of the medium for the ciucular resonant absorber were carried out to achieve an average absorption rate of 91.41%at 8~14μm.The optimizations of the inner and outer radius and thickness of the medium for the annular resonant absorber were carried out to achieve an average absorption rate of 93.33%at 8~14μm.The experimental results showd that the designed circular and annular resonators have realized the near-perfect absorption for 8~14μm at the infrared region.Different incident wave could stimulate the resonant vibration of the plasmons or local plasmons on the propagating surface.