Decoherence and turbulence sources in a long laser

TL;DR

This paper explores the initial phase of laser turn-on in long cavities, revealing how coherence develops from noise, with power fluctuations leading to dark solitons and turbulence influenced by cavity dispersion.

Contribution

It provides experimental insights into the stochastic turn-on process of long-delay lasers, highlighting the emergence of dark solitons and turbulence dynamics.

Findings

Power drop-outs seed dark solitons

Dark solitons exhibit chaotic behavior

Turbulence depends on cavity dispersion

Abstract

We investigate the turn-on process in a laser cavity where the roundtrip time is several orders of magnitude greater than the active medium timescales. In this long delay limit the electromagnetic field build-up can be mapped experimentally roundtrip after roundtrip. We show how coherence settles down starting from a stochastic initial condition. In the early stages of the turn-on, we show that power drop-outs emerge, persist for several round-trips and seed dark solitons. These latter structures exhibit a chaotic dynamics and emit radiation that can lead to an overall turbulent dynamics depending on the cavity dispersion.