PARAMETRIC GENERATION OF TUNABLE INFRARED RADIATION IN ZNGEP2 AND GASE PUMPED AT 3 MU-M

Traveling-wave parametric generators with angular tuning with the use of ZnGeP2 and GaSe crystals pumped by 100-ps pulses from an actively mode-locked Er laser (lambda almost-equal-to 3 mum) are reported. The continuous-tuning range achieved was 4-10 mum (ZnGeP2; length, 12 mm) and 3.5-18 mum (GaSe; length, 12 mm) in a type-I interaction, with a quantum conversion efficiency of a few percent. In the case of ZnGeP2 (length, 42 mm) and type-II phase matching, the pump threshold was 0.35 GW/cm2 and the quantum efficiency achieved was 17.6%, corresponding to an output peak power of 3 MW near 5-6 mum.