Plasmon-enhanced second harmonic generation in semiconductor quantum dots close to metal nanoparticles

TL;DR

This paper demonstrates a significant enhancement of second harmonic generation in semiconductor quantum dots due to proximity to silver nanoparticles, with the enhancement tunable by laser frequency, indicating nanoparticle-induced modification of nonlinear emission.

Contribution

It presents the first experimental evidence of plasmon-enhanced second harmonic generation in semiconductor quantum dots near metal nanoparticles.

Findings

Second harmonic signal is enhanced by about 1000 times.

Enhancement increases when laser frequency approaches silver plasmon resonance.

Silver nanoparticles modify the nonlinear optical emission of quantum dots.

Abstract

We report the enhancement of the optical second harmonic signal in non-centrosymmetric semiconductor CdS quantum dots, when they are placed in close contact with isolated silver nanoparticles. The intensity enhancement is about 1000. We also show that the enhancement increases when the incoming laser frequency $\omega$ is tuned toward the spectral position of the silver plasmon at $2\omega$, proving that the silver nanoparticle modifies the nonlinear emission.