Collective suppression of optical hyperfine pumping in dense clouds of atoms in microtraps

TL;DR

This paper reports on the collective suppression of optical hyperfine pumping in dense cold rubidium atom clouds, attributed to resonant dipole-dipole interactions, supported by experimental observations and stochastic electrodynamics simulations.

Contribution

It demonstrates density-dependent suppression effects in hyperfine optical pumping due to dipole-dipole interactions in microtrap atom arrays, combining experimental data with advanced simulations.

Findings

Suppression of Raman transition rate increases with atom density

Strong dipole-dipole interactions explain the suppression effect

Simulations match experimental results, confirming the collective behavior

Abstract

We observe a density-dependent collective suppression of optical pumping between the hyperfine ground states in an array of submicrometer-sized clouds of cold rubidium atoms. The suppressed Raman transition rate can be explained by strong resonant dipole-dipole interactions that are enhanced by increasing atom density. The observations are consistent with stochastic electrodynamics simulations that incorporate the effects of the nonlinear population transfer via internal atomic levels embedded in a coupled-dipole model.