基于TiN和TiO2的可见光至近红外线波段的超宽带吸收器

Ultra-broadband Absorber Working in the Range of Visible Light to Near-infrared Band Based on Titanium Nitride and Titanium Dioxide

超宽带吸收是电磁吸收器追求的一个重要目标。本文设计了一种基于氮化钛和二氧化钛两种耐火材料的槽深渐变的光栅型光吸收器,采用有限元法分析了单元结构的周期、凹槽深度、凹槽宽度、涂层厚度和凹槽个数对吸收曲线的影响,并确定了各个结构参数的最优值。该吸收器利用电介质腔共振效应和表面等离子体共振效应对入射电磁波进行吸收。结果表明:在优化结构参数条件下,在500~2000 nm波段范围内和0~80°入射角范围内,该吸收器的平均吸收率可达到90%以上,并且对入射角表现出不敏感性,实现了对可见光至近红外线波段电磁波的超宽带吸收。通过比较发现,凹槽顶部和底部采用半圆柱形结构时,吸收效果更优。由于构成该吸收器的材料为耐火材料,因此这种吸收器可以在高温环境下工作。该设计在光伏发电等领域有潜在的应用价值。

Ultra-wideband absorption is an important goal for electromagnetic absorbers.In this paper,a grating-typeoptical absorber with tapered groove depth based on titanium nitride and titanium dioxide refractories was designed to achieve ultrawideband absorption of electromagnetic wave from visible light to near-infrared band.The finite element method was used to analyze the influence of unit structure period,groove depth,groove width,coating thickness and groove number on the absorption curve,and the optimal value of each structure parameter was determined.The physical absorption mechanism of the absorber is dielectric cavity resonance effect and surface plasmon resonance effect.The results show that,with the optimal structure parameters,the average absorptivity of the absorber can reach more than 90%in the range of 500~2000 nm,and the absorption bandwidth is 1500 nm,covering most of the visible to near-infrared bands.In addition,the absorber maintains high absorption rate in the range of 0~80°incident angle,which shows that it is insensitive to the incident angle.Through comparison,it is found that the absorption effect of the semicylindrical structure at the top and bottom of the groove is better than that of the flat plate structure.As the material of the absorber is refractory,it can work in high temperature environment.This design has potential application value in photovoltaic power generation and other fields.