At the threshold of distributed Kerr-lens mode-locking in a Cr:ZnS waveguide laser

TL;DR

This paper explores the potential for distributed Kerr-lens mode-locking in a mid-IR Cr:ZnS waveguide laser, highlighting nonlinear mode coupling and the possibility of forming spatiotemporal solitons for scalable laser design.

Contribution

It introduces the concept of spatiotemporal mode-locking in Cr:ZnS waveguides and discusses the conditions for Kerr-lens mode-locking in energy-scalable solid-state lasers.

Findings

Efficient power scaling with intra-mode beatings.

Observation of Q-switching due to nonlinear mode-coupling.

Potential for forming spatiotemporal dissipative solitons.

Abstract

We demonstrate feasibility of spatiotemporal mode-locking in a mid-IR Cr:ZnS waveguide laser based on the nonlinear spatial mode coupling. The experiment shows efficient power scaling with the excitation of intra-mode beatings, causing a pronounced Q-switching which could cause a nonlinear mode-coupling. We suggest that a particularly high nonlinearity in Cr:ZnS combined with multimode waveguide leads to a soft aperture induced by a pump beam. The latter provides an effective spatial mode control in a nonlinear multimode waveguide and, thereby, opening the way to the birth of a spatiotemporal dissipative soliton, or light bullet, formation. Thus, forming the basis for the future distributed Kerr-Lens Mode Locking in the energy-scalable solid-state waveguide (or yet unrealized fiber) laser.