Pulse-width reduction in a diode-pumped doubly Q-switched YVO4/Nd:YVO4 laser with electro-optic modulator and GaAs saturable absorber

By using both a beta-BaB2O4 (BBO) electro-optic (EO) modulator and a GaAs saturable absorber, a laser-diode (LD) end-pumped doubly Q-switched YVO4/Nd:YVO4 laser is realized. A symmetric factor is defined to describe the temporal symmetry of output pulses. At 20 W incident pump power, a symmetric factor of 1.04 is obtained by the doubly Q-switched laser with 2.5 ns pulse width and 300 kW peak power. The experimental results show that the double Q-switching can generate a symmetric and shorter pulse with higher peak power in comparison with the single EO Q-switching. In order to explain these results, a rate equation model has been developed, and it leads to good agreement with the experimental data. (C) 2009 Optical Society of America