Abstract

In spite of the fact that short pulse technology has in last years decisively evolved towards solid state technology largely based on Ti:sapphire lasers in femtosecond region and diode pumped mode-locked oscillators in picosecond region, flashlamp pumping is still prevailing for pulsed high peak power Nd:YAG sources operated at low repetition rates. The main drawback of these actively-passively mode-locked flashlamp pumped Nd:YAG laser systems are liquid saturable absorber dyes used for mode-locking and Q-switching. The replacement of these dyes by a solid state element is most desirable. Attempts were made using gratings created in semiconductors, nonlinear mirrors based on second harmonic generation or to use the Kerr lens mode-locking. Recently we demonstrated combination of passive negative feedback using GaAs together with Cr:YAG as saturable absorber in an actively mode-locked Nd:YAG laser which led to stabilizing and stretching of the pulse trains to 150 ns and compression of individual pulses from 83 ps to 48 ps[1].

© 2000 IEEE