630nm to 3420nm tunable picosecond optical parametric laser emission from KTP crystal

Using a KTP crystal in the size of 6 .5x9x20 mm (length) , cut at 0 = 57° in X-Z plane, and with the second harmonic (532 nm) of the repetition rate mode-locked Nd:YAG laser light as the pumping source (pulse duration of 40 ps), tunable parametric laser emission from 630 nm to 3420 nm (in addition to those in the vicinity of degeneracy point) has been obtained by angle tuning for phase-matched type II OPG process. The maximum energy conversion efficiency is 30%, the peak power at the signal wave of 1300 nm is 20 NW.