Anisotropic fluorescence signals retarded dipole-dipole interactions in a thermal atomic cloud

TL;DR

This paper demonstrates how anisotropic fluorescence signals in a thermal atomic cloud are influenced by retarded dipole-dipole interactions, combining experimental observations with theoretical explanations at room temperature.

Contribution

It reveals the importance of retarded dipole-dipole interactions in shaping fluorescence signals, providing a comprehensive theoretical model matching experimental data.

Findings

Observation of anisotropic fluorescence signals in thermal vapors

Identification of retarded dipole-dipole interactions as key to spectral features

Theoretical model accurately reproduces experimental spectra

Abstract

We experimentally observe and theoretically explain anisotropic multiple quantum coherence signals in the fluorescence from dilute thermal potassium vapors, at room temperature and particle densities $\sim 10^8\ \rm{cm}^{-3}$. We identify the retarded part of the geometrically fully resolved inter-atomic, resonant dipole-dipole interaction as the crucial ingredient to theoretically reproduce all qualitative features of the experimental spectra.