中红外波段超广角抗反射微纳结构的研究

Research on Mid-infrared Ultra-wide-angle Anti-reflection Micro-nano Structure

采用时域有限差分法(FDTD)设计了一种具有超广角中红外波段减反射Si材料亚波长周期微纳结构,实现了在超广角(15°~80°)斜入射时大幅提高减反射性能。使用控制变量法分析了亚波长结构的周期、结构高度、底端直径和顶端直径对反射率的影响,并剖析结构参数对宽带和宽角度的影响机理。通过仿真计算研究表明:区别于传统的减反射结构,四棱台结构在中红外波段超广角入射时可以保持较低的反射率,平均反射率低至1%左右,最低可至0.01%,为超广角宽带抗反射结构的设计提供了新的设计方案。

In this paper,the finite difference time-domain(FDTD)method is used to design a subwavelength periodic micro-nano structure of Si material with ultra-wide angle medium infrared band,which can greatly improve the anti-reflection performance when the ultra-wide angle(15°~80°)oblique incidence occurs. The influence of the period,height,bottom diameter and top diameter of the subwavelength structure on the reflectivity is analyzed by using the control variable method;and the influence mechanism of the structure parameters on the broadband and wide angle is analyzed. The simulation results show that,different from the traditional anti-reflection structure,the four-prism structure can maintain a low reflectance when the ultra-wide-angle incident occurs in the middle infrared band,with the average reflectance as low as 1% and the lowest as low as 0.01%,providing a new design scheme for the ultra-wide-angle broadband anti-reflection structure design.