Optical parametric generation in the presence of strong two-photon absorption in periodically-poled LiNbO/sub 3/

Optical parametric oscillation (OPO) and optical parametric generation (OPG) have widely been used for producing tunable radiations. In this paper we present our results on the OPG pumped by a nanosecond 532-nm beam in a PPLN crystal. We have measured the OPG conversion efficiency for different repetition rates. In addition, we have also measured the transmittance of the pump beam and determined the two-photon absorption (TPA) coefficient of the PPLN crystal.