Analysis of surface relief diffraction gratings made of anisotropic material

A modal method for the analysis of surface relief gratings made with anisot ropic material is presented. The structure is decomposed into a series of c ascaded discontinuities between planar waveguides with stratified anisotrop ic dielectric. The basic problem is formulated by an integral equation whic h is solved numerically by the method of moments. The mode functions of the periodic region are assumed as basis functions to represent the unknown fi eld on the junctions. Each junction is viewed as a waveguide junction probl em and has been characterized by the generalized scattering matrix (GSM). T he diffraction efficiencies of the grating are determined by combining the various GSM. In this way, the analysis method is stable and can be applied also to deep gratings.