1.9 mJ at 1572 nm diode pumped passively Q-switched Nd:YAG slab laser with intracavity optical parametric oscillation

Summary form only given. We have presented here the highest, to our knowledge, peak power of 0.65 MW with 1.9 mJ energy at 1572 nm in a simple singly resonant diode pumped IOPO laser with 300 W diode array as a pump unit and a Nd:YAG slab as a gain medium. Applying the same pump unit optimized for a Q-switched operation laser with a Cr/sup 4+/:YAG passive Q-switch up to 5 mJ energy with peak power of 0.5 MW was demonstrated. The energy of 4.3 mJ in the fundamental mode at 1064 nm with 15 ns pulse duration in the passive Q-switched regime was achieved in the 200 mm long cavity arranged for IOPO with output coupler transmission of 40% at 1064 nm wavelength. A KTP crystal, of 5 /spl times/ 5 /spl times/ 20 mm size, ´x-cut´ for non-critically phase-matched parametric generation at the signal wavelength of 1572 nm, was used in experiments. It was shown in numerical modeling and experiments that following (after the strongest first pulse) weak pulses could be eliminated due to proper choice of output coupler transmission.