Observation of 2D dam break flow and a gaseous phase of solitons in a photon fluid

TL;DR

This paper demonstrates the experimental observation of 2D dam break flow and a soliton gas phase in a photon fluid, revealing complex nonlinear dynamics and collective phenomena in two-dimensional optical systems.

Contribution

It introduces the first observation of 2D dam break flow and soliton gas behavior in a photon fluid, expanding understanding of nonlinear wave dynamics beyond 1D systems.

Findings

Wave breaking occurs in both transverse dimensions.

Dispersive shock waves interact to form a 2D soliton ensemble.

A dynamic phase with a constant number of solitons is observed.

Abstract

We report the observation of a two-dimensional dam break flow of a photon fluid in a nonlinear optical crystal. By precisely shaping the amplitude and phase of the input wave, we investigate the transition from one-dimensional (1D) to two-dimensional (2D) nonlinear dynamics. We observe wave breaking in both transverse spatial dimensions with characteristic timescales determined by the aspect ratio of the input box-shaped field. The interaction of dispersive shock waves propagating in orthogonal directions gives rise to a 2D ensemble of solitons. Depending on the box size, we report the evidence of a dynamic phase characterized by a constant number of solitons, resembling a 1D solitons gas in integrable systems. We measure the statistical features of this gaseous-like phase. Our findings pave the way to the investigation of collective solitonic phenomena in two dimensions, demonstrating that the loss of integrability does not disrupt the dominant phenomenology.