Radiative and non-radiative effects of a substrate on localized plasmon resonance of particles

TL;DR

This study uses computational methods to analyze how substrates influence localized plasmon resonances in metallic nanoparticles, revealing complex radiative and non-radiative effects dependent on incident radiation parameters.

Contribution

It provides a detailed theoretical explanation of substrate effects on plasmon resonances, considering incident radiation angle, polarization, and particle shape, which was previously inconclusive.

Findings

Radiative coupling can both quench and enhance resonance.

Non-radiative interactions shift and enhance plasmon resonances.

Resonance effects depend on particle shape and incident radiation polarization.

Abstract

Experiments have shown strong effects of some substrates on the localized plasmons of metallic nano particles but they are inconclusive on the affecting parameters. Here we have used Discrete Dipole Approximation in conjunction with Sommerfeld integral relations to explain the effect of the substrates as a function of the parameters of incident radiation. The radiative coupling can both quench and enhance the resonance and its dependence on the angle and polarization of incident radiation with respect to the surface is shown. Non-radiative interaction with the substrate enhances the plasmon resonance of the particles and can shift the resonances from their free-space energies significantly. The non-radiative interaction of the substrate is sensitive to the shape of particles and polarization of incident radiation with respect to substrate. Our results show that plasmon resonances in coupled and single particles can be significantly altered from their free-space resonances and are quenched or enhanced by the choice of substrate and polarization of incident radiation.