Enhancement and suppression of surface plasmon resonance in Ag aggregate by optical gain and absorption in surrounding dielectric medium

TL;DR

This paper demonstrates how optical gain and absorption in surrounding dielectrics can enhance or suppress surface plasmon resonance in silver nanoparticle aggregates, with potential applications in nanoplasmonics.

Contribution

It reports the first experimental observation of loss compensation and suppression of surface plasmon resonance in silver nanoparticles through dielectric gain and absorption.

Findings

Six-fold enhancement of Rayleigh scattering indicating increased SP resonance quality

Experimental evidence of loss compensation in metal via dielectric gain

Suppression of SP resonance in absorbing dielectric environments

Abstract

We have observed the compensation of loss in metal by gain in interfacing dielectric in the mixture of aggregated silver nanoparticles and rhodamine 6G dye. The demonstrated six-fold enhancement of the Rayleigh scattering is the evidence of the increase of the quality factor of the surface plasmon (SP) resonance. The reported experimental observation paves the road to many practical applications of nanoplasmonics. We have also predicted and experimentally observed a suppression of the surface SP resonance in metallic nanoparticles embedded in a dielectric host with absorption.