A ZnGeP><sub>2</sub> (ZGP) optical parametric oscillator (OPO) with wide mid-IR tunability has been demonstrated. The singly resonant angle-tuned ZGP OPO was pumped by 100-ns erbium laser pulses at λ =2.93μm and yielded output that was continuously tunable from 3.8 to 12.4 μm (type I phase matching) and from 4 to 10 μm (type II phase matching). An OPO pump threshold was less than 1 mJ in the whole 4–12 μm range of the output, and the quantum conversion efficiency reached 35%. An OPO linewidth was typically a few wave numbers; however, with a single intracavity etalon (uncoated Si plate) in a type II OPO it was narrowed to <0.5cm<sup>-1</sup>. We demonstrate the sensitive detection of N<sub>2</sub>O gas with the narrow-linewidth OPO.
© 2000 Optical Society of America
(160.4330) Materials : Nonlinear optical materials
(190.2620) Nonlinear optics : Harmonic generation and mixing
(190.4360) Nonlinear optics : Nonlinear optics, devices
(190.4410) Nonlinear optics : Nonlinear optics, parametric processes
(190.4970) Nonlinear optics : Parametric oscillators and amplifiers
K. L. Vodopyanov, F. Ganikhanov, J. P. Maffetone, I. Zwieback, and W. Ruderman, "ZnGeP2 optical parametric oscillator with 3.8—12.4-μm tunability," Opt. Lett. 25, 841-843 (2000)