We report a high-repetition-rate (1–10-kHz) optical parametric oscillator (OPO) based on noncritically phase-matched ZnGeP<sub>2</sub> (ZGP).The pump source was an OPO based on periodically pole lithium niobate that was pumped in turn by a Q-switched diode-pumped 1-μm Nd:YAG laser. The ZGP OPO yielded continuously tunable output from 3.7 to 10.2μm by tuning of the pump wavelength from 2.3 to 3.7μm . At the optimal pump focusing, the minimum ZGP OPO threshold achieved was 2μJ, which is to our knowledge the lowest ever reported for a singly resonant OPO.The output energy in the 6–8-μ m range was >20μJ, and the quantum efficiency of converting 1-μm radiation to the mid IR exceeded 10%.
© 2003 Optical Society of America
K. L. Vodopyanov and P. G. Schunemann, "Broadly tunable noncritically phase-matched ZnGeP2 optical parametric oscillator with a 2-μJ pump threshold," Opt. Lett. 28, 441-443 (2003)