Diode End-Pumped 1.37 W Er:YSGG Continuous-Wave Laser around 2.8-μm

We demonstrate the laser performance of a LD end-pumped Er:YSGG crystals with different doping concentrations comparatively. The experimental results show that 30 at. % Er:YSGG crystal with dimensions of 2 mm $\times2$ mm $\times8$ mm has the best laser output. In continuous-wave (CW) mode and pulse mode, the maximum output powers of 1.37 and 1.20 W are achieved, corresponding to slope efficiencies of 23.62% and 22.91%, respectively. To the best of our knowledge, compared with other Er $^{3+}$ -doped garnet laser crystals, we obtained a larger power and higher efficiency CW laser simultaneously for LD end-pumped Er:YSGG crystal. The beam quality factor M2 in x and y directions are determined to be 1.64/1.65, suggesting the Er:YSGG laser possesses a higher beam quality. All these results indicate that Er:YSGG is a promising mid-infrared gain medium for high efficiency and high power laser operation.