Metal nanoparticle plasmons operating within quantum lifetime

TL;DR

This paper demonstrates that coupling a metal nanoparticle to a quantum emitter can significantly extend plasmonic oscillation lifetimes, enabling new quantum and energy applications through a phenomenon similar to electromagnetically induced transparency.

Contribution

It introduces a model showing how strong coupling with quantum emitters can dramatically increase plasmon lifetime, a novel approach in plasmonics research.

Findings

Plasmon lifetime can be increased up to the decay time of the quantum emitter.

The effect causes narrowing of the plasmon emission band.

Enhanced lifetime enables stimulated emission to surpass spontaneous emission.

Abstract

We investigate the dynamics of a plasmonic oscillation over a metal nanoparticle when it is strongly coupled to a quantum emitter (e.g. quantum dot, molecule). We simulate the density matrix evolution for a simple model; coupled classical--quantum oscillators system. We show that lifetime of the plasmonic oscillations can be increased several orders of magnitude, upto the decay time of the quantum emitter. This effect shows itself as the narrowing of the plasmon emission band in the spaser (surface plasmon amplification by stimulated emission of radiation) experiment [{\it Nature}, {\bf 2009}, 460, 1110], where a gold nanoparticle interacts with the surrounding molecules. Enhancement of the plasmonic excitation lifetime enables stimulated emission to overcome the spontaneous one. The enhancement occurs due to the emergence of a phenomenon analogous to electromagnetically induced transparency (EIT). The effect can find applications in many areas of nanoscale physics, such as in quantum information with plasmons and in increasing solar cell efficiency.