Widely tunable continuous-wave mid-infrared laser source based on difference-frequency generation in AgGaS 2

We demonstrate difference-frequency generation in the 6.8–12.5-μm range by mixing two high-power single-frequency laser diodes in a type II AgGaS2 crystal. This compact all-solid-state scheme provides maximum output powers that exceed 1 μW and permits continuous adjustment-free scans larger than 2 cm-1 across the entire tuning range.