Optical parametric processes in the presence of strong two-photon absorption

Abstract

Our experimental results indicate that the two-photon absorption sets the fundamental limits to optical parametric generation and oscillation in periodically-poled lithium niobate. The investigation of how the strong TPA affects the OPG and OPO pumped by a nanosecond 532-nm beam in a PPLN crystal. To our surprise, the OPG becomes more efficient for the signal generation. In addition, the TPA can be further enhanced by self-focusing caused by accumulated thermal effect (ATE) by multiple laser pusles