基于严格耦合波理论的多层介质膜光栅衍射特性分析

Diffraction property of multi-layer dielectric gratings studied by rigorous coupled-wave analysis

基于严格耦合波理论建立了多层介质膜光栅的衍射机理模型,给出了TE波自准直条件下多层介质膜光栅衍射效率的表达式.以-1级衍射效率为评价函数,分析了表面浮雕结构分别为HfO2和SiO2材料的介质膜光栅获得衍射效率优于96%的结构参数.数值计算表明,顶层材料为HfO2的介质膜光栅具有更宽的结构选择范围.最后分析了介质膜光栅的制备容差和允许的入射角度范围.

The rigorous coupled-wave analysis technique for describing the diffraction of multi-layer diffraction grating（MDG） is put forward.Formulations for a stable and efficient numerical implementation of diffraction efficiency are presented for MDG for TE polarization and Littrow angle.With the merit function of the-1 order diffraction efficiency higher than 96%,the parameters of MDG are optimized for HfO_2 and SiO_2 top layers,respectively.Numerical calculation indicates that a larger grating parameter range can be obtained with HfO_2 rather than the SiO_2 on the top.The manufacture tolerance and the effective incident angle for the optimized structure of MDG are discussed in the end.