Optical parametric oscillator of quasi-phasematched LiNbO_(3) pumped by a compact high repetition rate single-frequency passively Q-switched Nd:YAG laser

摘要

We report on an efficient diode pumped compact source of pulsed tunable infrared mdiation based on a high repetition rate single frequency passively Q-switched Nd:YAG laser and an optical parametric oscillator (OPO) of quasi-phase matched LiNbO_(3). When pumped by 5.4 W of 810 nm cw diode laser radiation the Nd:YAG laser (which is passively Q-switched by a Cr~(4+) :GSGG saturable absorber) oscillates on a single-longitudinal mode and emits in a diffraction limited beam light pulses with duration of 2 ns, pulse energy of 100 μJ, repetition rate of 1.1 kHz and average power of 110 mW. This radiation excites an OPO of quasi-phase matched LiNbO_(3). The OPO generates signal and idler radiation which is tunable in the range of 1.46-1.61 μm and 3.13-3.92 μm, respectively. Tuning is achieved by using 8 different poling pefiods (A = 28.5-29.9 μm) and by changing the crystal's temperature in the range of 80-160℃. The measured signal pulse energy is E_(s) = 22 μJ, the average signal output power P_(s) = 24 mW, the measured idler power P_(I) = 2.5 mW and the pump depletion 33%.