Transverse optical and atomic pattern formation

TL;DR

This paper reports experimental observation and theoretical modeling of transverse optical and atomic pattern formation in cold atoms at very low power levels, highlighting symmetry-breaking and reduced threshold conditions.

Contribution

It introduces a self-consistent model for pattern formation in cold atoms, demonstrating lower power thresholds using small detunings and sub-Doppler temperatures.

Findings

Pattern formation occurs at less than 1 microWatt power.

Symmetry-breaking is observed in optical and atomic structures.

Reduced intensity thresholds are achieved with cold atom conditions.

Abstract

The study of transverse optical pattern formation has been studied extensively in nonlinear optics, with a recent experimental interest in studying the phenomenon using cold atoms, which can undergo real-space self-organization. Here, we describe our experimental observation of pattern formation in cold atoms, which occurs using less than 1 microWatt of applied power. We show that the optical patterns and the self-organized atomic structures undergo continuous symmetry-breaking, which is characteristic of non-equilibrium phenomena in a multimode system. To theoretically describe pattern formation in cold atoms, we present a self-consistent model that allows for tight atomic bunching in the applied optical lattice. We derive the nonlinear refractive index of a gas of multi-level atoms in an optical lattice, and we derive the threshold conditions under which pattern formation occurs. We show that, by using small detunings and sub-Doppler temperatures, one achieves two orders of magnitude reduced intensity thresholds for pattern formation compared to warm atoms.