Dispersive Media Subcell Averaging in the FDTD Method using Corrective Surface Currents

TL;DR

This paper introduces a corrective subcell averaging technique for the FDTD method that enhances accuracy at dispersive material interfaces by modeling field discontinuities as surface currents, achieving near second-order precision.

Contribution

It proposes a novel effective-medium formulation that improves FDTD accuracy at dispersive interfaces by incorporating surface currents, which was not previously addressed.

Findings

Enhanced FDTD accuracy at dispersive interfaces.

Efficient computation with near second-order accuracy.

Effective modeling of field discontinuities as surface currents.

Abstract

We present a corrective subcell averaging technique that improves on the accuracy of the volume-averaged finite-difference time-domain (FDTD) method in the presence of dispersive material interfaces. The method is based on an alternative effective-medium formulation that captures field discontinuities at interfaces as electric and magnetic surface currents. In calculating the spectra of strongly dispersive Mie scatterers we demonstrate that the derived FDTD algorithm is both highly efficient and able to approximately restore second order accuracy.