Acousto-optic-modulator-stabilized low-threshold mode-locked Nd:YVO4 laser

A substantially low-threshold, kilohertz repetition rate and laser-diode-array pumped Nd:YVO4 laser, actively Q switched by an acousto-optic modulator and passively mode locked by a nonlinear mirror consisting of a KTiOPO4, second harmonic generating crystal, and a dichroic output coupler, is demonstrated with enhanced efficiency. The mode-locked pulses with a width of 11.5ps lie underneath a Q-switched envelope having a width of 58ns with a Q-switched modulation frequency of 40kHz. For 10W of pump power, a peak power of 719kW is obtained under stable Q-switched and mode-locked operation, which is a marked improvement compared to the earlier reports.