Frequency conversion of mid-IR lasers into the long-wavelength domain of 12-20 µm with AgGaSe2, BaGa2GeSe6 and PbIn6Te10 nonlinear crystals.

Difference frequency generation under mixing of repetitively-pulsed CO- and CO2-laser radiation in AgGaSe2, BaGa2GeSe6 and PbIn6Te10 nonlinear crystals was studied. Efficiency and refractive indices were examined for this frequency conversion into the long-wave domain of ∼12-20 µm in the mid-IR. The highest frequency conversion efficiency of 10-4 was obtained for a relatively new PbIn6Te10 crystal, which is an order of magnitude higher than previous results.

Sum frequency generation of multi-line slab radio frequency discharge carbon monoxide laser system with intracavity nonlinear BaGa2GeSe6 crystal.

A compact repetitively pulsed broadband carbon monoxide (CO) laser system with intracavity frequency conversion, for which a nonlinear crystal was also used as an output coupler, was launched for the first time, to the best of our knowledge. The laser system simultaneously operated in two spectral ranges: CO laser fundamental band (4.9-6.0 µm) and its sum frequencies band (2.45-2.95 µm). Different designs of the laser cavity were considered. Peak powers of the fundamental and sum frequencies laser pulses were up to 2 kW and 10 W, respectively.