Near-field plasmonics of gold nanoparticles in dielectric media

Abstract

Metal nanoparticles have attracted intense attention due to their unique optical and thermal properties for applications such as micro-nano electronics and photonics. Relative orientation, interparticle spacing, and particle size strongly impact the optical behavior of the nanoparticle assemblies. The near-field confinement of electromagnetic fields between closely packed metal nanoparticles, which is enhanced due to their plasmonic behavior, creates high thermal energy densities under visible to near-infrared wavelength laser irradiation. As metal nanoparticles tend to be oxidized or change shape under laser illumination, resulting in non-linear optical and thermal behavior, surrounding each metal nanoparticle with a dielectric shell could be a potential way to mitigate these effects as well as to engineer their plasmonic behavior. In this study, we use numerical simulations to analyze the plasmonic behavior of gold (Au) nanoparticles surrounded with dielectric shell by investigating nanoparticle's various configurations to each other as well as their relative orientation to incoming light source under laser irradiation in dielectric media. Such geometries are of particular interest for applications such as photonic integrated circuits, photonic sintering and nanophotonic cooling.