Laser performance of Tm:(LuGd)GaO crystal in 2-2.3 μm spectral region.

Continuous-wave (CW) and acousto-optic (AO) Q-switched laser operations based on Tm:LGGG crystal have been investigated in the spectral region of 2-2.3 μm. In CW regime, laser emissions at 2006 nm, 2160 nm, and 2344 nm are obtained by using different cavity mirrors with selective coating. A maximum output power of 4.25 W is achieved at 2006 nm with a slope efficiency of 32.8%. By suppressing the intense laser emissions at around 2 μm, a total output power of 0.925 W at 2160 nm and 2344 nm is obtained, corresponding to a slope efficiency of 12.9%. Furthermore, single laser wavelength operation at 2344 nm is realized by suppressing the laser emissions within 2-2.2 μm, delivering a maximum output power of 0.27 W and a slope efficiency of 5.1%. To the best of our knowledge, this is the first demonstration of laser emissions at 2160 nm and 2344 nm for Tm:LGGG crystal. However, by using an acousto-optic modulator (AOM), only Q-switching laser operation is obtained at 2004 nm, and the shortest pulse width of 216 ns and maximum pulse energy of 600 μJ are obtained, corresponding to a maximum pulse peak power of 2.78 kW.