High order FDTD methods for transverse magnetic modes with dispersive interfaces

A new finite-difference time-domain (FDTD) algorithm is introduced to solve two dimensional (2D) transverse magnetic (TM) modes with a straight dispersive interface. Driven by the consideration of simplifying interface jump conditions, the auxiliary differential equation of the Debye constitution model is rewritten to form a new Debye–Maxwell TM system. Interface auxiliary differential equations are utilized to describe the transient changes in the regularities of electromagnetic fields across a dispersive interface. The resulting time dependent jump conditions are rigorously enforced in the FDTD discretization by means of a matched interface and boundary scheme. Higher order convergences are numerically achieved for the first time in the literature in 2D FDTD simulations of dispersive inhomogeneous media.