Q-factor and absorption enhancement for plasmonic anisotropic nanoparticles

TL;DR

This paper explores how radially anisotropic dielectric layers in core-shell nanoparticles enhance their Q-factor and absorption rates, with potential applications in plasmonic scattering and absorption.

Contribution

It demonstrates that anisotropic dielectric layers can significantly improve the resonance quality and absorption efficiency of plasmonic nanoparticles, and proposes practical layered structures to realize such anisotropy.

Findings

Radially anisotropic dielectric layers accelerate evanescent decay of surface modes.

Absorption cross section can reach the single resonance limit.

Artificial anisotropic cladding can be achieved with layered isotropic materials.

Abstract

We investigate the scattering and absorption properties of anisotropic metal-dielectric core-shell nanoparticles. It is revealed that the radially anisotropic dielectric layer can accelerate the evanescent decay of the localized resonant surface modes, leading to Q-factor and absorption rate enhancement. Moreover, the absorption cross section can be maximized to reach the single resonance absorption limit. We further show that such artificial anisotropic cladding materials can be realized by isotropic layered structures, which may inspire many applications based on scattering and absorption of plasmonic nanoparticles.