Multiple self-organized phases and spatial solitons in cold atoms mediated by optical feedback

TL;DR

This paper investigates the complex self-structuring phenomena in cold atomic clouds driven by optical feedback, revealing multiple phases and the existence of spatial solitons with potential applications in atomic trapping.

Contribution

It introduces a detailed analysis of self-organization in cold atoms mediated by optical feedback, including phase diagrams and the discovery of feedback solitons.

Findings

Identification of hexagonal, stripe, and honeycomb phases depending on interaction strength

Recovery of inversion symmetry in the stripe phase

Existence of light-density feedback solitons acting as atomic traps

Abstract

We study the transverse self-structuring of a cloud of cold atoms with effective atomic interactions mediated by a coherent driving beam retro-reflected by means of a single mirror. The resulting self-structuring due to optomechanical forces is much richer than that of an effective-Kerr medium, displaying hexagonal, stripe and honeycomb phases depending on the interaction strength parametrized by the linear susceptibility. Phase domains are described by real Ginzburg-Landau amplitude equations. In the stripe phase the system recovers inversion symmetry. Moreover, the subcritical character of the honeycomb phase allows for light-density feedback solitons functioning as self-sustained dark atomic traps with motion controlled by phase gradients in the driving beam.