ABSTRACT
This chapter describes a perfect matched layer (PML) for Fourier modal method (FMM). A PML is an artificial layer that permits the accurate calculation of the distribution of an electromagnetic field inside the computational region by satisfying outgoing wave conditions. Since FMM was first developed to analyze diffraction properties of binary gratings with a fixed period, it has employed periodic boundary conditions and assumes an infinite space along the lateral direction. The performance of a PML is specified in terms of isolation between neigh-boring cells and the preservation of properties of eigenmodes. To the contrary, FMM can be used to solve an electromagnetic field in the spatial Fourier domain. This configuration is a good example showing that, by using the PML, the numerical simulation of an isolated super-cell is possible in FMM.
