Finite-Difference Time-Domain NIodelling

The usual, highly efficient, modelling tools for planar optical devices are generally not suitable for modelling photonic crystal structures. For example, the Beam Propagation Method fails when applied to these strongly scattering structures since presumptions are made on the propagation direction of the waves. The Finite-Difference Time-Domain method (FDTD), however, as a direct discretisation of Maxwell's equations, does not suffer from such restrictive assumptions. I t will be shown that the evolution of the electromagnetic field in both time and space-as calculated using FDTD- can be of considerable help in understanding the physics of photonic crystal structures