High-power/high-brightness diode-pumped 1.9-/spl mu/m thulium and resonantly pumped 2.1-/spl mu/m holmium lasers

TLDR

The authors resonantly end‑pump a Ho:YAG laser using the 1.91‑μm emission from a high‑brightness diode‑pumped Tm:YLF laser, achieving ~19 W continuous‑wave output. The study demonstrates a diode‑pumped Tm:YLF laser delivering >36 W at 1.91 μm (M²≈2) and, when used to resonantly end‑pump Ho:YAG, yields ~19 W CW output with ~18 % optical‑to‑optical efficiency; a Q‑switched configuration further achieves >16 W at 15 kHz (M²≈1.48) and a 9–>50 kHz frequency range.

Abstract

We report high power (>36 W) with beam propagation factor M/sup 2//spl sim/2 in a diode end-pumped Tm:LiYF/sub 4/ (Tm:YLF) laser generating output near the 1.91-/spl mu/m region. Using the 1.91-/spl mu/m emission and high brightness achieved with the Tm:YLF laser we resonantly end-pump the Holmium /sup 5/I/sub 7/ manifold in Ho:YAG and demonstrate /spl sim/19 W of continuous-wave (CW) output. The diode-to-Holmium optical to-optical conversion efficiency achieved is /spl sim/18%. Using a CW pumped and repetitively Q-switched configuration, the Tm:YLF pumped Ho:YAG laser achieves >16 W of output power with an M/sup 2//spl sim/1.48 at 15 kHz. A Q-switched frequency range of 9 to >50 kHz is also achieved.