Efficient Tm:LuVO_4 laser at 19 μm

We report an efficient laser-diode-pumped Tm-doped LuVO₄ crystal laser at about 1.9 μm. For the first time to our knowledge, the π-polarized Tm:LuVO₄ laser was achieved. The maximum output power and slope efficiency were 1.32 W and 28.7%, respectively. By comparison, it has been found that the a-cut Tm:LuVO₄ crystal should be more suitable for applications in high-power lasers. The central laser wavelength was observed to be located at about 1.9 μm and shifted to shorter with the increase of intracavity light intensity, which could be explained based on the reabsorption of light in the Tm:LuVO₄ crystal.