Diode-pumped mid-infrared Tm:YGG laser at 2.0 and 2.3 μm

In this work, we demonstrate the continuous-wave (CW) mid-infrared laser performances of thulium-doped yttrium-gallium garnet (Tm:YGG). A high-quality crystal with 3.5 at.% Tm3+-doping concentration was grown by the optical floating zone method. The absorption and emission cross-section spectra of Tm:YGG were calculated at room temperature. For F-3(4) -> H-3(6) transition, the maximum output power was improved to 1.27 W at the free-running wavelength 2012 nm, with a slope efficiency of 28.8%. By inserting a birefringent filter, a continuously tunable laser ranging from 1949 nm to 2036 nm was realized. In addition, as far as we know, we obtain the first laser operation around 2355 nm in H-3(4) -> H-3(5) transition. The maximum output power is 152 mW and the slope efficiency is 3.3%. These results should be helpful for optimizing the laser performances and potential applications of thulium-doped active materials.

Automated summary

In this study, we demonstrate the optimization and potential applications of thulium-doped yttrium-gallium garnet (Tm:YGG) in continuous-wave mid-infrared lasers. By adjusting the doping concentration and using birefringent filters, high-power output and continuous tunability of the lasers were achieved.