Purcell-Dicke effect for an atomic ensemble near a surface

TL;DR

This paper investigates the combined Purcell-Dicke effect where an atomic ensemble's superradiant emission is enhanced by both collective atomic effects and dielectric environments, demonstrating environment-induced modifications and tunability.

Contribution

It introduces a model treating the ensemble as a single effective N+1-level system and explores how dielectric surfaces influence superradiance and Casimir-Polder interactions.

Findings

Environment alters superradiant emission dynamics.

Enhanced and anisotropic Casimir-Polder potential observed.

External laser field provides tunability of the effect.

Abstract

The emission by an initially completely inverted atomic ensemble in the long-wavelength regime is simultaneously enhanced by both collective effects (Dicke effect) and dielectric environments (Purcell effect), thus giving rise to a combined Purcell-Dicke effect. We study this effect by treating the ensemble of N atoms as a single effective N+1-level 'Dicke atom' which couples to the environment-assisted quantum electrodynamic field. We find that an environment can indeed alter the superradiant emission dynamics, as exemplified using a perfectly conducting plate. As the emission acquires an additional anisotropy in the presence of the plate, we find an associated resonant Casimir-Polder potential for the atom that is collectively enhanced and that exhibits a superradiant burst in its dynamics. An additional tuneability of the effect is introduced by applying an external driving laser field.