Type II sum frequency generation in flux and hydrothermally grown KTP at 1. 319 and 1. 338. mu. m

Type II noncritically phase matched sum frequency generation by mixing of the 1.319 and 1.338 {mu}m lines of a Q-switched Nd:YAG laser with their seconds harmonics is demonstrated. Results are presented for KTP crystals grown by both the hydrothermal and the flux technique. A temperature acceptance width-length product of 8.5 {plus minus} 0.5{degrees}C.cm was determined. Type II critical phase matching at room temperature, for three different propagation/polarization orientations, is also demonstrated. The differences in the angles required for phase matching between crystals grown by the different techniques are quantified.