Modeling pulse shape of Q-switched lasers

A general approach describing the pulse shape and temporal width of Q-switc hed lasers has been derived, Based on a normalized intermediate variable de scribing the ratio of population inversion density at the beginning of Q-sw itch to that at threshold, a generalized characteristic equation that gover ns passively and actively Q-switched lasers is derived, From the characteri stic equation, the pulse symmetry property and pulse width can be described and easily calculated for any given operating parameters, and the waveform of the laser pulse can be reconstructed without solving the laser rate equ ations. An approach is also given for the case of intracavity frequency-dou bled Q-switched lasers, Theoretical results show agreement with experiments for a diode pumped Nd:YAG laser system that is passively Q-switched by a C r4+ :YAG absorber.