在入射平面内小角度入射一维光栅零级衍射场的简便计算方法

摘要

The rigorous couple wave analysis( RCWA) is one of die most common methods for the study of grating diffraction. For the incident beam normal to the surface of die grating, the positive and negative N diffraction orders are same due to the symmetry.which lead to the great amplified in by decreasing matrix size from 2N+1 to N+ 1. In this paper,the simplified method is extended to the case that the incident plane parallel to the grating line. Id this case,the problem of matrix size 2(2N + 1) (due to the coupling of different polarization states) can be reduced to die problem of matrix size 2(N+ 1). Furthermore, some more simple approach for the small incident angle is discussed, in which the problem of matrix size 2(N+ 1) can be reduced to (N+ l).The typical simulation shows that the error is acceptable in quite a large range, which is important in practical use.%耦合波分析法(RCWA)方法是目前研究光栅衍射最普遍的方法.垂直入射到光栅表面的光使衍射光的正负N级衍射波处于对称状态,使得在RCWA法中原先需要计算2N+1级衍射的2N+1阶矩阵问题降低到计算N+1级衍射的N+1阶矩阵问题.本文将这种对称结构的简化方法推广到非垂直入射、光栅条纹在入射平面内的情况,使得在这种耦合情况下的2(2N+1)阶矩阵问题简化为2(N+1)阶矩阵问题.同时针对小角度入射的情况提出了进一步简化计算方法将其简化为(N+1)阶矩阵问题.实验表明在较大的范围内,其误差均可接受,在工程应用具有重要的意义.