100 Hz high energy KTiOAsO4 optical parametric oscillator

A high energy KTiOAsO4 (KTA) optical parametric oscillator (OPO) pumped by a 1064 nm MOPA system was demonstrated. The characteristics of the high energy middle infrared laser output were studied with the 41.2°-cut (in XZ plane) and X-cut KTA crystals. At 100 Hz, 74.5 mJ of 1.49 μm signal and 24.6 mJ of 3.75 μm idler were obtained with the 41.2°-cut KTA OPO, corresponding to slope efficiencies of 50% and 16.7% for the signal and idler. With the X-cut KTA OPO, 89.7 mJ of 1.54 μm signal and 33.8 mJ of 3.46 μm idler were obtained, corresponding to slope efficiencies of 36.4% and 15%.