Analysis of the methods for controlling the emission dynamics of pulsed lasers in order to generate long trains of ultrashort pulses

Calculations are reported of the process of generating long trains of ultrashort pulses with identical energies in two laser systems with active mode locking. Various methods of dynamic control of the cavity Q factor are considered. It is shown that the maximum energy in a flat-topped train is governed entirely by the parameters of the initial cavity losses and that the most effective control systems are those with double negative feedback. Experiments are reported on the generation, in a pulsed YAG : Nd laser with active mode locking, of trains with more than 100 ultrashort pulses whose average energy is ~2.1 μJ.