Compact, actively Q-switched optical parametric oscillator

An ultracompact, actively Q-switched optical parametric oscillator (OPO) ha s been realized that is only 30 mm in length, based on a semimonolithic mic rochip laser, a quadrupole deflector, and a monolithic periodically poled l ithium niobate crystal. The OPO threshold was 550 mW when Nd:YAG was used a s thr:gain material and 590 mW for Nd:YVO4, giving signal pulses of as much as 8.7 mu J in energy with Nd:YAG at 1 kHz and 5.9-mu J pulses with Nd:YVO 4 at 5 kHz, for 1.2- and 2-W laser diode pumping, respectively. The output was single frequency and could be tuned over the range 1540-3440 nm. (C) 19 99 Optical Society of America.