CALCULATION METHODS AT THE PLASMONIC. 3. FINITE DIFFERENCE TIME DOMAIN

Abstract

The article presents the third part of the review of computational methods that are actively used in the problems of plasmonics, namely, the method of integrating Maxwell's equations in the time domain (FDTD). The FDTD method is a direct implementation of time-dependent Maxwell equations for solving a temporary change in electromagnetic waves within a finite space containing an object of arbitrary geometry and composition. In practice, the space is discretized by a grid of the grid, and the existence of the scattering particle is determined by the proper assignment of the electromagnetic constants, including dielectric permittivity, permeability and conductivity over the grid points. Maxwell's Rolling Equations are subsequently discretized using convergence of approximation with a difference both in time and in space. The main advantages of this method lie in several aspects. First, the whole range-frequency band can only be obtained by one calculation in the time domain. Secondly, the simplicity of an explicit numerical FDTD scheme. The FDTD method can easily simulate complex objects. However, the universality of the method imposes high requirements for computing, so for real simulation it is necessary to optimize to improve the efficiency of the calculation. One of these optimization options is the parallelization of computations. It is shown that it is an efficient calculation within this model. To show the effectiveness of the application of FDTD in plasmonic problems, the original results of the authors of the simulation of the optical spectra of a metal ball and the pair of interacting metal balls of different sizes are presented. Also, the results of simulation of the local amplification of the electromagnetic field of light waves, obtained by the authors, are presented in the article. Both numerical experiments give results similar to those obtained on an experiment. The simulation of the interaction between particles can be used to solve the inverse problem, to determine the distance between metal particles from absorption spectra of plasmon material. The simulation shows the local amplification of the wave field of light, which was fixed by the authors and for real samples of metal films.

Keywords: modeling, plasmonics, approximation, finite difference time domain method, paralleling, local fields