Experimentally confirmed design guidelines for passively Q-switched microchip lasers using semiconductor saturable absorbers

We present a model for passively Q-switched microchip lasers and-derive sim ple equations for the pulse width, repetition rate, and pulse energy. We ex perimentally verified the validity of the model by systematically varying t he relevant device parameters. We used the model to derive practical design guidelines for realizing operation parameters that can be varied in large ranges by adoption of the parameters of the semiconductor saturable-absorbe r mirror and choice of the appropriate gain medium. Applying these design g uidelines, we obtained 37-ps pulses, which to our knowledge are the shortes t pulses ever generated in a passively Q-switched solid-state laser. (C) 19 99 Optical Society of America [S0740-3224(99)00503-2]. OCIS codes: 140.3480 , 140.3540, 140.3580,140.3530, 140.3500, 160.6000.