Generation of tunable mid-IR (5.5–9.3 μm) from a 2-μm pumped ZnGeP2 optical parametric oscillator

Abstract A tunable mid-infrared optical parametric oscillator (OPO) has been demonstrated using a single ZnGeP 2 (ZGP) crystal. A KTP OPO was pumped by an Nd:YAG laser to generate 2.02 μm-signal wave at the output, which is used for pumping a singly resonant angle-tuned ZGP OPO to generate mid-IR tunable from 5.5 to 9.3 μm. Maximum pump to idler (2–8 μm) conversion efficiency obtained, was ∼8.25%, which corresponds to ∼32% quantum efficiency.