Moving towards high-power thin-disk lasers in the 2-{\mu}m wavelength range

TL;DR

This paper reports a significant advancement in high-power thin-disk lasers operating at around 2.1 micrometers, achieving over 100 W of continuous-wave power in the mid-infrared range, marking a milestone for industrial and scientific applications.

Contribution

The authors demonstrate a single-mode CW Ho:YAG thin-disk laser exceeding 100 W, surpassing previous records and paving the way for ultrafast and high-power mid-infrared laser applications.

Findings

Achieved 112 W output power at 2.1 μm with 54.6% efficiency.

Surpassed previous single-mode TDL power levels by a factor of over 4.

System is suitable for future modelocking and ultrafast amplification.

Abstract

Thin-disk lasers (TDLs) have made spectacular progress in the last decades both in continuous-wave and ultrafast operation. Nowadays, single thin-disk oscillators with > 16 kW of continuous-wave (CW)-power have been demonstrated and ultrafast amplifiers have largely surpassed the kilowatt milestone with pulse energies in the multi-100 mJ range. This amazing development has been demonstrated in the 1-{\mu}m wavelength range, using Yb-doped materials and supported by industrially available components. Motivated by both strong scientific and industrial applications, interest in expanding this performance to longer wavelength regions continues to increase. In particular, TDLs emitting directly in the short-wave mid-infrared (SW-MIR) region (2-3 {\mu}m) are especially sought after, and although many early studies have been reported, most remained in the proof-of-principle stage and the potential for multi-100-W operation remained undemonstrated. Here, we report on our recent results of a single fundamental-mode CW Ho:YAG thin-disk oscillator with >100 W of power, surpassing previous single-mode TDLs by a factor of >4, and marking a first milestone in the development of high-power SW-MIR TDLs. In optimized conditions, our laser system emitting at {\guillemotright} 2.1 {\mu}m reaches an output power of 112 W with 54.6-% optical-to-optical efficiency and an M2 = 1.1. This system is ideally suited for future direct modelocking at the 100 W level, as well as for ultrafast amplification. We start the discussion with a review of the state-of-the-art of TDLs emitting directly in the vicinity of 2 {\mu}m, and then discuss difficulties and possible routes both towards ultrafast operation and next possible steps for power scaling.