W/VO_2方形纳米柱阵列可调中红外宽频吸收器

Tunable Mid-Infrared Broadband Absorber Based on W/VO_2 Square Nano-Pillar Array

基于VO_2的热致相变特性,仿真设计出了一种W/VO_2方形纳米柱阵列可调中红外宽频吸收器,通过时域有限差分法分析了结构参数对吸收性能和结构内电磁场强度分布的影响,以及吸收器在不同偏振态和入射角度下的吸收特性。结果表明:在最佳的结构参数下,当VO_2未发生相变时,入射到吸收器的红外光转变为热而消耗掉,在3～5μm谱段的平均吸收率高达96.2%;当VO_2发生相变而转变为金属相时,吸收器表现出强反射,抑制吸收,高低温下的平均吸收率差可达74.1%。该吸收器的吸收率受入射光的影响较小,具有广角吸收特性,有望在红外智能光电领域得到应用。

Based on the thermochromic phase transition characteristics of VO2,a tunable mid-infrared broadband absorber with a W/VO2 square nano-pillar array is designed.The influences of structural parameters on the absorption performances and the electromagnetic field intensity distributions within the structure,and the absorption characteristics of the absorber under different polarization states and incident angles are analyzed by the finite difference time domain method.The results show that the infrared light incident on the absorber is converted into heat and consumed when VO2 does not undergo the phase transition,and the average absorptivity of the absorber in 3-5μm wavelength region is as high as 96.2%under the optimal structural parameters.In contrast,the absorber exhibits a strong reflection and inhibits light absorption when the phase of VO2 is changed into a metallic state,and the average absorptivity difference between high and low temperatures can reach 74.1%.The absorptivity of the absorber is less affected by the incident lasers with different polarization states and has wide-angle absorption characteristics,so the absorber is expected to be applied in the field of infrared intelligent optoelectronics.