A picosecond IR laser system with tunable wavelength, based on a hybrid CO_2 laser

This paper describes a picosecond laser system based on a hybrid CO_2 laser, using optically controlled semiconductor switches with a pulse width from 100 ps to 300 ns, followed by conversion of the radiation in nonlinear crystals by means of second-harmonic generation. Silver selenogallate AgGaSe_2 and zinc germanium diphosphide ZnGeP_2 are used as nonlinear crystals. Two-stage conversion of the radiation of a picosecond CO_2 laser with wavelength 9.4-10.6 μm into laser radiation with wavelengths 4.7-5.3 μm is carried out in the apparatus with an efficiency of 0.3%-0.5%, while 4.7-5.3-μm radiation is converted into 2.4-2.65-μm radiation with an efficiency of 8%. The overall conversion efficiency is 4×10^−4 or 0.04% for an output pulse energy up to 35 μJ.