A new formulation of the Fourier modal method (FMM) that applies the correctrules of Fourier factorization for crossed surface-relief gratings is presented.The new formulation adopts a general nonrectangular Cartesian coordinate system, which gives the FMM greater generality and in some cases the ability to savecomputer memory and computation time. By numerical examples, the new FMM isshown to converge much faster than the old FMM. In particular, the FMM isused to produce well-converged numerical results for metallic crossed gratings.In addition, two matrix truncation schemes, the parallelogramic truncationand a new circular truncation, are considered. Numerical experiments showthat the former is superior.
© 1997 Optical Society of America
Lifeng Li, "New formulation of the Fourier modal method for crossed surface-relief gratings," J. Opt. Soc. Am. A 14, 2758-2767 (1997)