Gaussian dispersion analysis in the time domain: Efficient conversion with Padé approximants

We present an approach for adapting the Gaussian dispersion analysis (GDA) of optical materials to time-domain simulations. Within a GDA model, imaginary part measured dielectric function is presented as sum absorption terms. Such simple model valid where inhomogeneous broadening substantially larger than homogeneous linewidth. The essential broadband approximation many glasses, polymers, and other natural artificial with disorder. However, efficient implementation this in full-wave electromagnetic solvers has never been fully achieved. start causal form isolated oscillator Gaussian-type - Causal Dawson-Gauss oscillator. Then, we derive explicit analytical formulas implement finite-difference (FDTD) solver minimal use memory floating point operations. derivation FDTD employ our generalized dispersive material (GDM) universal, modular describing Pad\'e approximants. share prototype codes that include automated generation approximants universal employs various second-order accurate numerical schemes. can be used non-commercial commercial software simulations light propagation media, which are experimentally characterized models.