Collective spontaneous emission of two atoms near metal nanoparticle

TL;DR

This paper develops a quantum-mechanical model for superradiance of two atoms near a metal nanoparticle, showing that the nanoparticle accelerates collective emission and analyzing efficiency limitations due to non-radiative losses.

Contribution

It introduces a wave-function-based quantum approach to collective emission near nanoparticles, extending superradiance theory to include nanoparticle interactions.

Findings

Nanoparticles accelerate collective spontaneous emission.

Radiation from two emitters is faster than from separated systems.

Efficiency is limited by non-radiative losses but consistent for single and multiple emitters.

Abstract

We present quantum-mechanical approach for collective spontaneous emission (superradiance) of emitters (as atoms) near metal nanoparticle, when frequencies of transitions of emitters coincide with frequency of localized plasmon resonance of the nanoparticle. Our approach is based on Schrodinger description and it uses wave functions of states of systems. Interactions between emitters and between the nanoparticle and emitters are taken into account. We consider an example of two emitters and show that radiation is occurred through symmetric states of emitters as it is in Dicke model of superradiance. The nanoparticle accelerates collective spontaneous emission similar how it accelerates spontaneous emission of single emitter. Radiation from two emitters near the nanoparticle is faster than the radiation from two separated and non-interacted "nanoparticle+single emitter" systems. Efficiency of superradiance, i.e. the ratio of emitted photons to total number initial excitations in the system, is smaller than 1 due to non-radiative losses in the nanoparticle. However the efficiency is the same for single and for two emitters near the nanoparticle. The approach can be straightforwardly generalized to the case of many emitters near the nanoparticle.