Spectral Solution for Scattering Analysis of Periodic Plasmonic Nano-antennas on Iso/Anisotropic Substrate

Abstract

A fast solution for the scattering analysis of periodic plasmonic nano-antennas (PPNAs) on iso/anisotropic substrates is presented. This method is based on derivation of the spectral dyadic Green's function with taking into account the plasmonic effects. The obtained dyadic Green's function is then used in an integral equation formulated for computing the induced surface current densities on the PPNAs. The resultant integral equation is solved by means of Galerkin's Method of Moments with entire-domain basis and test functions. With the help of this computational technique, the scattering characteristics of several examples are analyzed. The computed results are validated by means of a full-wave EM solver based on finite element method. For showing the efficiency of this method, the convergence rate and computation time in terms of space harmonic orders are calculated. It is shown that the developed method is an efficient and speedy technique for the analysis of such periodic plasmonic structures. In addition, we study an array of PPNAs on a uniaxial anisotropic substrate where the scattering characteristics are calculated as a function of the optic-axis direction. It is found that using anisotropic materials as the substrate of PPNAs allows additional degrees of freedom for controlling the scattering information.