Diode-pumped doubly Q-switched mode-locked YVO4/Nd:YVO4/KTP green laser with AO and GaAs saturable absorber

Abstract By using both acousto-optic modulator and GaAs saturable absorber, a diode-pumped Q-switched and mode-locked(QML) YVO4/Nd:YVO4/KTP green laser is presented. The experimental results show that the doubly QML YVO4/Nd:YVO4/KTP green laser has good stability and nearly 100% modulation depth. The average output power and the pulse width of the Q-switched envelope have been measured. The mode-locked pulse inside the Q-switched envelope has a repetition rate of 137 MHz and its pulse width is estimated to be about 280 ps. By using a hyperbolic secant square function and considering the Gaussian distribution of the intracavity photon density, the coupled equations for diode-pumped dual-loss-modulated QML green laser is given and the numerical solutions of the equations are in good agreement with the experimental results.