Picosecond synchronously pumped ZnGeP2 optical parametric oscillator.

We report on the experimental operation of a picosecond, singly resonant, synchronously pumped optical parametric oscillator (SPOPO) based on a ZnGeP(2) (ZGP) crystal. The ZGP SPOPO is pumped with the idler radiation from a diffraction-grating-tuned periodically poled lithium niobate SPOPO emitting a continuous picosecond pulse train (Delta tau approximately 8 ps, f=76 MHz). The noncritically 90 degree phase-matched ZGP SPOPO is tuned in the 3.8-5.6 microm range by tuning the pump wavelength (2.25-2.5 microm). As high as approximately 800 mW of average power is emitted at 4 microm.