Abstract:An mid-infrared optical parametric oscillator based on passively Q-switched periodically poled Mgo∶LiZbO3 (PPMgLN) was studied.Nd∶YVO4/Cr4+∶YAG passively Q-switched laser is used as pump sources,the output of 7.78W at 1064nm is obtained,and the pulse width is 10ns and the repetition is 50 kHz.Under the effect of frequency doubling crystal PPMgLN,the output of 360 mw idle light at 3.2 μm is obtained,an optical-to-optical efficiency is 20%. The periodically poled range of the PPMgLN crystal is from 29μm to 31.5μm. The OPO could be tuned over 3.0~4.0μm in the combination of period tuning and temperature tuning.