Watt-level diode-pumped Tm:YVO₄ laser at 2.3 µm

In this Letter, a watt-level laser diode (LD)-pumped ∼2.3-µm (on the ³H₄→³H₅ quasi-four-level transition) laser is reported based on a 1.5 at.% a-cut Tm:YVO₄ crystal. The maximum continuous wave (CW) output power obtained is 1.89 W and 1.11 W with the maximum slope efficiency of 13.6% and 7.3% (versus the absorbed pump power) for the 1% and 0.5% transmittance of the output coupler, respectively. To the best of our knowledge, the CW output power of 1.89 W we obtained is the highest CW output power amongst the LD-pumped ∼2.3-µm Tm³⁺-doped lasers.