Diode-pumped bifunctional Nd:LGSB laser passively Q-switched by a Cr4+:YAG saturable absorber

We report on the output performances of a fiber-coupled diode pumped Nd:LGSB laser passively Q-switched by a Cr 4+ :YAG saturable absorber (SA), with emissions at 1.06-μm near-infrared wavelength, as well as at 0.53-μm visible green spectrum through the self-frequency doubling process. The 2.3-at.% Nd:LGSB crystal delivered 1.43 W continuous-wave power at 1.06 μm with an overall optical-to-optical efficiency (with respect to the absorbed pump power) of 0.50. Green light with 3.3-mW power was emitted in a free-generation regime at 1.95-W absorbed pump power. By employing a Cr 4+ :YAG SA crystal with initial transmission T i = 0.89, laser pulses at 1.06 μm with 13.4-μJ energy at 17.1-kHz repetition rate were obtained for ∼1.8 W absorbed pump power. The green laser pulse energy was 0.21 μJ at a 37.7-kHz repetition rate. The pulse duration amounted to 4.8 ns for both wavelengths of emission, indicating pulse peak power of 2.8 kW and 43.7 W for operation at 1.06 μm and 0.53 μm, respectively.