Investigations and Comparisons of Active Q-Switching Laser Performances of Composite and Conventional Nd:YVO4 Crystals with Electro-Optic Modulator

Actively Q-switched laser performances of composite and conventional Nd:YVO4 crystals were investigated and compared with different Nd-doped concentrations of laser media and different repetition rates of electro-optic modulator. Both continuous-wave and actively Q-switched operations were realized experimentally. At an incident pump power of 7.69 W, the shortest pulse duration of 6.5 ns was obtained by the composite Nd(0.1 at.%):YVO4/Nd(0.3 at.%):YVO4/Nd(0.8 at.%):YVO4 crystal at the repetition rate f = 2 kHz. However, the composite Nd(0.1 at.%):YVO4/Nd(0.5 at.%):YVO4/Nd(1.0 at.%):YVO4 laser achieved the maximum average output power of 687 mW at f = 10 kHz and the largest single pulse energy of 144 mu J at f = 2 kHz. Power saturation of the conventional Nd:YVO4 crystal was shown during experiment, while no power saturation was observed on the composite Nd:YVO4 crystals, showing good thermo-mechanical performances.