中红外波段仿蛾眼表面高斯面形抗反射微纳结构优化

Simulation and Optimization of Bionic Moth-Eye Antireflective Microstructures with Periodic Gaussian Top Surface Array in Mid Infrared Range

基于严格耦合波分析理论,设计中波红外波段3~5μm的仿生蛾眼表面高斯面形周期阵列抗反射微纳结构,用三维有限时域差分法进行仿真模拟优化,分析了结构阵列周期、占空比、刻蚀深度对反射率和透过率的影响,比较高斯面形、抛物面形、圆锥形结构模型抗反射效果,给出了最优化参数组合。分析了加工过程中周期、占空比和刻蚀深度以及外部形状轮廓偏差对蛾眼微纳结构的影响,给出了在要求抗反射效果下允许的结构参数公差尺寸范围和建议加工尺寸,结果得到的抗反射结构反射率低于3%~5%,透过率高于90%。

The optical properties, in mid infrared range （3 -5μm）, of the bionic moth eye antireflective micro-nanostructure with periodic Gaussian top surface array, were empirically approximated, mathematically modeled, theoretically analyzed in rigorous coupled-wave analysis（RCWA） theory, numerically simulated 3-D in finite-difference time domain （FDTD） method, and experimentally evaluated for design optimization. The impact of the periodicity, duty cycle and etching depth on the reflectivity and transmittance and the dependence of the antireflection on Gaussian, parabolic and conical top surfaces were investigated. Thetransmittanee and antireflective efficiency of thebionic moth-eyewith the optimized geometry were found to be over 90% and below 3% -5% ,respectively. In addition, the structural parameters and fabrication tolerance were tentatively discussed.