We present a 3~5 μm optical parametric oscillator (OPO) based on ZGP pumped by KTP OPO 2.1-μm laser. The tuning curves of ZGP OPO are calculated. The x 6 x 18 (mm) ZGP crystal, whose end faces are antireflection coated at 2.1 and 3.7~4.6 μm, is cut as Θ =53.5o, Φ =0o. When the pump power of 2.1-μm polarized laser is 15 W at 8 kHz, 5.7-W output power and 46.6% slope efficiency are obtained with a ZGPtype I phase match. Central wavelengths of the signal and idler lasers are 4.10 and 4.32 μm, respectively. Pulse duration is about 27 ns. Beam quality factor M<sup>2</sup> is better than 1.8. The tunability of 3~5 μm can be achieved by changing the angle of the ZGP crystal.
© 2011 Chinese Optics Letters
(140.3070) Lasers and laser optics : Infrared and far-infrared lasers
(140.3580) Lasers and laser optics : Lasers, solid-state
(140.3600) Lasers and laser optics : Lasers, tunable
(190.4970) Nonlinear optics : Parametric oscillators and amplifiers
Yuefeng Peng, Xingbin Wei, and Weimin Wang, "Mid-infrared optical parametric oscillator based on ZnGeP2 pumped by 2- μm laser," Chin. Opt. Lett. 9, 061403- (2011)