Transformation Optics Approach to Plasmon-Exciton Strong Coupling in Nanocavities

TL;DR

This paper develops a transformation optics method to analyze plasmon-exciton strong coupling in nanocavities, revealing how emitter placement influences coupling to dark modes and enabling reversible quantum dynamics.

Contribution

It introduces a quasi-analytical transformation optics approach to thoroughly explore plasmon-exciton interactions in nanocavities, highlighting the impact of emitter positioning on coupling to dark modes.

Findings

Coupling to multipolar dark modes increases when the emitter is placed away from the cavity center.

Reversible quantum dynamics can be achieved in feasible nanocavity implementations.

The approach allows detailed exploration of the hybrid system's plasmonic spectrum.

Abstract

We investigate the conditions yielding plasmon-exciton strong coupling at the single emitter level in the gap between two metal nanoparticles. A quasi-analytical transformation optics approach is developed that makes possible a thorough exploration of this hybrid system incorporating the full richness of its plasmonic spectrum. This allows us to reveal that by placing the emitter away from the cavity center, its coupling to multipolar dark modes of both even and odd parity increases remarkably. This way, reversible dynamics in the population of the quantum emitter takes place in feasible implementations of this archetypal nanocavity.