FDTD Potentials for Dispersion Analysis of Sinusoidally Modulated Media

A numerical study based on the finite difference time domain (FDTD) method is presented for the oblique incidence of TE modes with an emphasis on dispersion properties. The proposed medium has sinusoidally modulated dielectric permittivity. In order to truly address this scattering problem, total fieldscattered field (TFSF) approach is suggested, which yields accurate results for the electric field distribution inside the modulated medium. A comparison between analytical plots and the FDTD results reveals the ability of FDTD in rigorous analysis of band diagrams for any arbitrary value of modulation factor. In addition, a closed form formula for numerical dispersion relation is derived for the case of small modulation.