Efficient dielectric function for FDTD simulation of the optical properties of silver and gold nanoparticles

We have developed an efficient parameterization of the dielectric properties of Au and Ag in the energy range between 0.6 eV and 6.6 eV. The resulting time-domain dielectric function can be used for finite-difference time-domain (FDTD) simulations of the optical properties of nanoparticles. We present FDTD calculations of the extinction spectra of various Au and Ag nanoparticles and show that the calculated spectra agree very well with exact calculations using experimentally measured dielectric functions.