TEMPORAL CHARACTERISTICS AND DYNAMICS OF GAIN-SWITCHED CR-YAG LASERS

Temporal characteristics of tuned and fixed-wavelength Cr:YAG gain-swi tched oscillators are presented for 1064 nm Nd:YAG laser excitation. T hree temporal excitation regimes have been studied with the pump laser operating in free-running and e-switched modes. Characteristic satura tion and rollover behaviour of the Cr:YAG output energy with increasin g pump energy is examined in terms of pump pulse duration, polarizatio n orientation and fluence. Increased pump spot sizes yield higher valu es for the optimum pump energy and effective Cr:YAG energy scaling is demonstrated with only a slight threshold increase. A further enhancem ent in efficiency is obtained using 500 ns pump pulses. Control of the Cr:YAG pulse duration in the 160-300 ns range is obtained, using 6-80 ns pump pulses. The Cr:YAG laser output is shifted to the near infrar ed region using second harmonic generation in KTP.