Investigation of a diode-pumped double passivelyQ-switched Nd:GdVO4laser with a Cr4+:YAG saturable absorber and a GaAs coupler

A diode-pumped double passively Q-switched Nd:GdVO4 laser with a Cr4+:YAG saturable absorber and a GaAs coupler is realized for the first time to our knowledge. This laser can generate symmetric pulse temporal profiles and shorter pulses with higher peak powers when compared with the single passively Q-switched laser. To understand the results obtained in the experiment, we introduce a rate equation model in which the spatial distributions of the intracavity photon density, the pump beam and the population-inversion density are taken into account. The numerical solutions of the rate equations are consistent with the experimental results.