Numerical Simulation of Broadband Scattering by Coated and Noncoated Metal Nanostructures Using Discrete Dipole Approximation Method

Abstract

We suggest numerical method to study the optical response of metal nanostructures. The analysis of optical properties such as scattering and absorption by coated and noncoated nanogeometry has been done using discrete dipole approximation (DDA) method. The core-shell nanogeometry supports surface plasmon resonances, which are highly tunable from 400 to 1100 nm. The tunability of surface plasmon resonance (SPR) highly depends on the structural anisotropy and chosen core-shell material. Further, we have observed that aspect ratio is one of the key parameter to decide the nature and position of the plasmonic peaks and magnitude of optical cross section. We have also shown that coated nanospheroid is a more appropriate geometry as compared to coated nanosphere and noncoated nanospheroid in terms of wide tunability of surface plasmon resonance. The wide tunability in SPR is observed for the effective radii 90 nm core-shell (Au@SiO 2 ) nanospheroid with aspect ratio 0.1.

Scattering characteristics of dual Gaussian beams by a uniaxial anisotropic coated sphere

“…The methods for investigating electromagnetic scattering of coated spheres can be divided into numerical and analytical methods. Among them, numerical analysis methods include the time-domain finite series method, the method of moments and the discrete dipole method [7][8][9]. In contrast, the analytical method is to use Maxwell's equations for strict derivation, thus obtaining the exact solution of the model, so it has a more profound physical significance.…”