Integral equation method with parametrization of grating profile theory and experiments

Theories and their numerical implementations to rigorously solve Maxwell's equations are fundamental in diffractive optics. Various rigorous methods have been developed in the past which allow the analysis and synthesis of diffraction gratings. The basis of the great majority of rigorous methods is the Fourier series expansion of the permittivity function. Unfortunately the Fourier expansion can easily give poor results for the TM mode. By using an integral method with parametrization of the grating profile this problem can be overcome for surface modulated gratings. The theory and a comparison of theoretical and experimental results are presented.