Diode-pumped quasi-cw intracavity optical parametric oscillator at 1.57 mum with efficient pulse shortening

We report on a passively Q-switched diodepumped Nd:YAG laser including an i ntracavity optical parametric oscillator, that generates 120-mu J pulses wi th 1.6ns time duration (75 kW peak power) at 1572 nm with excellent beam qu ality (M-2 approximate to 1.1) and pulse amplitude fluctuation approximate to 2%. The passively Q-switched laser alone, pumped by a 200-Hz repetition rate, 80-W peak-power single diode bar, produced linearly polarized pulses of 12 ns and 460 mu J energy at 1064 nm. A different: more complex cavity s etup optimizing the passive Q-switching yielded 160-mu J 2-ns signal pulses with slightly increased peak power.