Diode-pumped passively Q-switched mode-locked c-cut Nd:GdVO/sub 4//KTP Green laser with a GaAs wafer

A diode-pumped passively Q-switched mode-locked (QML) intracavity frequency-doubled c-cut Nd:GdVO
₄
/KTP green laser with a GaAs saturable absorber is presented. Nearly 100% modulation depth for the mode-locked green pulses has been achieved. By using the hyperbolic secant function methods and considering the influences of continuous pump rate and the stimulated radiation lifetime of the active medium, a modified rate equation model for Q-switched and mode-locked lasers was proposed. With this modified model, the theoretical calculations are in good agreement with the experimental results, and the width of the mode-locked green pulse was estimated to be about 300 ps