Enhanced FDTD edge correction for nonlinear effects calculation

An edge correction has been developed providing a considerable enhancement of the accuracy in electromagnetic field calculation. This edge correction is based on a modification of the material parameters in the vicinity of the edge. For non equidistant grids the integrals in the given equation here in the paper have to be calculated for each gridpoint corresponding to the edge which requires a slightly increased effort in the preprocessing. However, beside the modification of the material matrix, the calculation algorithm has been retained unchanged. Thus the numerical effort for the time step iteration loop stays the same.