Time development of ultrashort pulse generation from a Nd:glass laser with a saturable dye and short laser pulse damage of GaAs and ZnTe at 1.06 microns

The fluctuation theory of ultrashort pulse (USP) generation in a Nd:glass laser with a saturable absorber, according to Letokhov, is outlined. When the lasing threshold is reached, many ultrashort fluctuation spikes grow independently of one another, until the strongest spike acquires sufficient intensity to saturate and bleach the absorber. The fast relaxation of the absorber precludes weaker spikes from passing through while it is still in the bleached state. The strongest spikes then experience a nonlinear growth and evolve into the output pulse train, until the population inversion in the active medium is fully depleted. Laser damage experiments on GaAs and ZnTe with passively Q-switched nanosecond pulses and mode-locked picosecond pulse trains at 1.06 microns were carried out.