Comparative study of plasmonic antennas for strong coupling and quantum nonlinearities with single emitters

TL;DR

This paper establishes conditions for strong coupling between a single quantum emitter and plasmonic nanostructures, analyzing various geometries to optimize Rabi splitting for quantum plasmonic applications.

Contribution

It provides an analytical condition for strong coupling with plasmonic nanocavities and studies optimal geometries for Rabi splitting with single quantum emitters.

Findings

Analytical condition for strong coupling established

Numerical analysis of Rabi splitting in various nanostructures

Identification of optimal geometries for strong coupling

Abstract

Realizing strong coupling between a single quantum emitter (QE) and an optical cavity is of crucial importance in the context of various quantum optical applications. While Rabi splitting of single quantum emitters coupled to high-Q diffraction limited cavities have been reported in numerous configurations, attaining single emitter Rabi splitting with a plasmonic nanostructure is still elusive. Here, we establish the analytical condition for strong coupling between a single QE and a plasmonic nanocavity and apply it to study various plasmonic arrangements that were shown to enable Rabi splitting. We investigate numerically the optical response and the resulting Rabi splitting in metallic nanostructures such as bow-tie nanoantennas, nanosphere dimers and nanospheres on a surface and find the optimal geometries for emergence of the strong coupling regime with single QEs. We also provide a master equation approach to show the saturation of a single QE in the gap of a silver bow-tie nanoantenna. Our results will be useful for implementation of realistic quantum plasmonic nanosystems involving single QEs.