一种宽波段减反的新型苞状蛾眼结构模拟研究

Simulation of Broadband Anti-Reflective and Bud-Shaped Moth-Eye Structure

基于传统抛物面蛾眼结构(PSMS)的优良减反性能,设计出一种具有抛物线中心截面的新型苞状蛾眼结构(BSMS)。采用时域有限差分法(FDTD),通过对比PSMS在不同底面直径和高度下的平均反射率,确定了最佳底面直径为200 nm;在此基础上分析了PSMS、BSMS及圆锥形蛾眼结构(CSMS)在不同高度下的反射率大小和截面电场强度分布,并通过等效介质理论对BSMS的减反性能进行进一步理论分析。结果表明:在300~1200 nm波段和300~1000 nm高度范围内,BSMS的平均反射率均低于PSMS及CSMS;当底面直径为200 nm、高度为800 nm时,BSMS的平均反射率低至0.19%,减反效果约为PSMS的3.5倍,约为CSMS的3.8倍,具有优异且平稳的抗反射性能,为减反结构的进一步设计和优化提供了参考。

A new bud-shaped moth-eye structure(BSMS) with a parabolic center section was designed based on the excellent anti-reflection performance of the traditional parabola-shaped moth-eye structure(PSMS). With the finite-difference time-domain(FDTD) method, we determine the best bottom diameter to be 200 nm by comparing the average reflectance of PSMSs with different bottom diameters and heights. On this basis, the reflectance and cross-sectional electric field intensity distribution of PSMS, BSMS, and a cone-shaped moth-eye structure(CSMS) at different heights were analyzed. Furthermore, the anti-reflection performance of BSMS was assessed with the equivalent medium theory. The results show that the average reflectance of BSMS is lower than that of both PSMS and CSMS in the wavelength range of 300--1200 nm and the height range of 300--1000 nm;when the bottom diameter is 200 nm and the height is 800 nm, the average reflectance of BSMS is as low as 0.19%, and its anti-reflection effect is about 3.5 times that of PSMS and 3.8 times that of CSMS. BSMS demonstrating excellent and stable anti-reflection performance provides a reference for the further design and optimization of anti-reflection structures.