High power tunable infrared radiation has been generated by difference frequency mixing in the non-linear crystals LiNb03 and AgGaS2. A commercially available system in which one to ten millijoules per pulse in the spectral region of 1.5 to 4.5 microns is described. Also discussed is work being performed to extend the range of the instrument to 12 microns.
J J Jacob, J J Jacob,
"Broadly Tunable Mid-Infrared Radiation By Difference Frequency Mixing", Proc. SPIE 0461, New Lasers for Analytical & Industrial Chemistry, (23 May 1984); doi: 10.1117/12.941066; https://doi.org/10.1117/12.941066