Self-mode locking in a diode-pumped self-Q-switched green laser

Simultaneous self-mode locking and self-Q switching in a diode-pumped intracavity frequency doubled Cr4+:Nd3+:YAG/KTP green laser operating at 532 nm is presented. Nearly 100% modulation depth for self-mode-locked green pulses has been achieved and a maximum average output power of 132 mW was obtained at an incident pump power of 5.72 W. By using a hyperbolic secant function method, considering the Gaussian spatial distribution of the intracavity photon density and the influences of continuous pump rate, as well as the stimulated radiation lifetime of the active medium and the excited-state lifetime of the saturable absorber, a rate equation model was introduced to reconstruct the Q-switched and mode-locked lasers. The theoretical results are in good agreement with the experimental results, and the width of the self-mode-locked green pulse was estimated to be about 350 ps. (c) 2007 American Institute of Physics.