**4. Conclusion**

This chapter presents the results obtained in the numerical simulation of a passively Qswitched solid state laser system generating high power, high output energy singular laser pulses or laser pulses trains in pulsed CW or quasi-CW pumping. An important feature of the developed simulation method consists of an analysis of the differences between the first passively Q-switched laser pulse and the next, generated by a CW or a quasi-CW pumped laser system, regarding the recovery condition to the initial state of the passive optical Qswitch cell, which is analyzed in detail for the first time. As far as we know, concerning the passive optical Q-switching, this difference is not reported in literature so far as exhaustively studied. By observing this difference, a method for estimation of laser output pulse parameters is developed. The numerical simulation results are compared to the experimental data and a fairly good agreement between them is observed.
