Theoretical and experimental study on a diode-pumped actively Q-switched Nd:GdVO4 self-stimulated Raman laser at 1173Â nm

By using Nd:GdVO4 as the gain medium and the Raman medium simultaneously, the actively Q-switched operation of the self-Raman Nd:GdVO4 laser at 1173 nm was realized. The output characteristics versus the incident pump power and the pulse repetition rates were investigated. At a pulse repetition rate of 30 kHz an average power up to 1.22 W was obtained with the incident pump power of 9.6 W, corresponding to a conversion efficiency of 12.7% with respect to the diode laser input power. In the theoretical part, the rate equations with the Gaussian distributions of the intracavity photon density and the initial population inversion density taken into account were used to describe the Raman pulse characteristics. By considering a more precise expression of the focal length of the thermal lens, the obtained theoretical results were in good agreement with the experimental results for all the incident pump powers.