Control of the pulse width in a diode-pumped passively Q-switched Nd:GdVO4/KTP green laser with a Cr4+:YAG saturable absorber

Different techniques to control the pulse width of a diode-pumped passively Q-switched Nd:GdVO4/KTP green laser have been theoretically and experimentally studied. It is shown that, when we vary the positions of the saturable absorber in the laser axis and the pump beam waist in the gain medium, we obtain an efficient means to control the pulse width. The experiments performed on a diode-pumped Nd:GdVO4/KTP green laser passively Q-switched by a Cr4+:YAG saturable absorber are consistent with the theoretical calculations obtained from the rate equation model, in which the intracavity photon density that is assumed to be the Gaussian spatial distribution, the longitudinal variation of the intracavity photon density, and the pump beam spatial distribution are also considered.