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.dThe 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 MIX, for TE polarization and Littrow angle. With the merit function of the - I 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.National Natural Science Foundation of China [10376040]; Scientific Research Foundation of the Education Bureau of Shandong Province, China [J06P02