Performance enhancement of diode-end-pumped quasi-three-level continuous-wave and passively Q-switched Nd:Gd3Ga5O12 lasers

Abstract We present the results on diode-end-pumped quasi-three-level lasers in continuous-wave and passively Q-switched regimes using a weakly Nd3+ doped Gd3Ga5O12 (GGG) crystal as active medium. In continuous-wave case, a maximum output power of 8.06 W at 937 nm is achieved with a slope efficiency of 47.3%. In passively Q-switched case, a simultaneous dual-wavelength laser at 937 nm and 933 nm is obtained with a maximum output power up to 1.72 W. The corresponding shortest pulse width is 21.1 ns at a repetition rate of 32.8 kHz, which leads to maximum pulse energy and peak power of 52.4 μJ and 2.48 kW, respectively. We believe that the present results represent the best that have ever achieved at this emission band in diode-end-pumped Nd:GGG lasers. Thus, for quasi-three-level laser, a weakly doped laser active medium could be an effective way for power scaling owing to thermal alleviation and reduction of reabsorption loss.