Passively Q-Switched Tm:CaGdAlO_4 laser using a Cr^2+:ZnSe saturable absorber

Diode-pumped Tm:CGA lasers at 1938 and 1854 nm are reported in continuous-wave and Q-switched regimes. For continuous-wave laser operation, the maximum output powers for the two lasers are 3.05 and 2.41 W with slope efficiencies of 33.7% and 28.5%, respectively. For Q-switching, using a Cr:ZnSe saturable absorber, the maximum average output powers reach 0.64 and 0.37 W with corresponding shortest pulse widths, maximum pulse repetition rates, maximum pulse energies and maximum pulse peak powers of (44ns, 13.9 kHz, 46 μJ, 1.04 kW) and (47 ns, 9.9 kHz, 37.4 μJ, 0.79 kW), respectively.