MMP simulation of coupled gold nanoparticles as nanoantennae: Efficient tuning of localized surface plasmon resonances

Abstract

We study localized surface plasmon excitations on a set of two coupled two-dimensional (2D) gold nanoparticles as a nanoantenna by using the multiple multipoles (MMP) method. We investigate the plasmon spectrum as a function of the nanoparticle's size, the background index of refraction, and the separating gap between the nanoparticles in order to provide proper means to tune the underlying plasmon resonance efficiently. Accurate multiple multipoles (MMP) computations are conducted with precise control over error measures, particularly for configurations of coupled particles with varying inter-particle distances and illumination conditions. Our findings demonstrate that by selecting these parameters carefully, nanoantennae can amplify emitter radiation across a wide range of spectra from ultraviolet to near-infrared. Numerical calculations have revealed that the MMP method is accurate, easy to handle, and efficient even on a low-cost, state-of-the-art PC.