Optical wave turbulence and condensation of light

TL;DR

This paper reports an optical wave turbulence regime where photons undergo an inverse cascade driven by six-wave interactions, leading to soliton formation and nonlinear dynamics in light propagation.

Contribution

It demonstrates the occurrence of wave turbulence and photon condensation in an optical system through experimental observation of inverse cascades and soliton development.

Findings

Inverse photon cascade observed in optical turbulence

Six-wave resonant interactions drive the cascade

Formation and evolution of solitons along the beam

Abstract

In an optical experiment, we report a wave turbulence regime that, starting with weakly nonlinear waves with randomized phases, shows an inverse cascade of photons towards the lowest wavenumbers. We show that the cascade is induced by a six-wave resonant interaction process and is characterized by increasing nonlinearity. At low wavenumbers the nonlinearity becomes strong and leads to modulational instability developing into solitons, whose number is decreasing further along the beam.