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

Vyacheslav Shatokhin, Friedemann Landmesser, Mario Niebuhr, Frank Stienkemeier, Andreas Buchleitner, Lukas Bruder

Published: 2025/8/15

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.