The pulse shape of a passively Q-switched microchip laser

The shape of the intensity pulse of a passively Q-switched microchip laser is investigated numerically and analytically. Our analysis is motivated by independent microchip laser experiments exhibiting nearly symmetric pulses in the case of a semiconductor saturable absorber and asymmetric pulses in the case of a solid state saturable absorber. Asymptotic methods are used t o determine limiting behaviors of the pulse shape for both symmetric and as ymmetric pulses. In the first case, we determine a sech(2) solution paramet rized by one parameter which can be determined by solving two coupled nonli near algebraic equations. In the second case, the pulse solution is decompo sed into two distinct approximations exhibiting different amplitude and tim e scares properties. We review earlier approximations of the repetition rat e and the pulse width.