基于严格耦合波理论的多层介质膜光栅衍射特性分析

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. 关键词： 衍射效率 多层介质膜光栅 严格耦合波理论

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

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 HfO₂ and SiO₂ top layers, respectively. Numerical calculation indicates that a larger grating parameter range can be obtained with HfO₂ rather than the SiO₂ on the top. The manufacture tolerance and the effective incident angle for the optimized structure of MDG are discussed in the end.