Strongly enhanced light-matter interaction in a hybrid photonic-plasmonic resonator

TL;DR

This paper introduces a hybrid photonic-plasmonic resonator that significantly enhances light-matter interaction by combining a metal nanoparticle with a whispering gallery mode microcavity, maintaining high quality factors and boosting single-atom cooperativity.

Contribution

It demonstrates a novel hybrid structure that greatly improves light-matter coupling efficiency while preserving high-Q properties, surpassing single microcavity or nanoparticle systems.

Findings

Single-atom cooperativity increased by over two orders of magnitude.

High-Q whispering gallery modes are maintained despite the presence of the nanoparticle.

The hybrid system offers advantages for quantum and nonlinear optics, as well as biosensing.

Abstract

We propose a hybrid photonic-plasmonic resonant structure which consists of a metal nanoparticle (MNP) and a whispering gallery mode (WGM) microcavity. It is found that the hybrid mode enables a strong interaction between the light and matter, and the single-atom cooperativity is enhanced by more than two orders of magnitude compared to that in a bare WGM microcavity. This remarkable improvement originates from two aspects: (1) the MNP offers a highly enhanced local field in the vicinity of an emitter, and (2), surprisingly, the high-\textit{Q} property of WGMs can be maintained in the presence of the MNP. Thus the present system has great advantages over a single microcavity or a single MNP, and holds great potential in quantum optics, nonlinear optics and highly sensitive biosening.