硅基中长波红外减反微结构研究

Antireflective silicon based microstructures for the mid-and long-wavelength infrared

采用微加工工艺在Si衬底上制备了微柱和微锥阵列,结合光学建模分析,研究了结构参数对中长波(2.5~9μm)红外光反射率的影响规律。使用严格耦合波分析方法(RCWA)计算的微结构反射光衍射效率与傅里叶红外变换光谱仪(FTIR)测试的反射率结果吻合较好。研究结果表明,Si基微结构对TM及TE偏振光均有良好的红外光减反特性,微锥结构具有更好的减反效果,2.5~6.5μm中红外偏振光的反射率低至2%,同时表现出良好的宽谱与广角度减反特性。

Si based micro-pillar arrays and micro-cone arrays were fabricated using micro processing technology, the reflection performance of the micro structures was studied in the long wave infrared wavelengths （2.5-9μm） reflection performance of different polarized light. Micro-fabrication combined with modeling analysis of silicon based micro-pillar and micro-cone arrays have been performed to study the effects of structural parameters on the reflectivity of infrared light from 2.5-9μm. Simulation results using rigorous coupled wave analysis （RCWA） method is in line with the test results from a Fourier transform infrared spectrometer （FTIR）. It is found that the antireflection characteristics can be obtained for both transverse electric （TE） and transverse magnetic （TM） polarizations, and the microcone arrays have lower reflectivity than the micro-pillar arrays. Moreover, the optimized micro-cone arrays show a reflectivity of only 2% or lower from 2.5-6.5 μm under TM polarization, with wide- spectrum and omnidirectional antireflection characteristics.