Abstract

A non-critically phase-matched KTA OPO produces a 30 % efficient source of 4 pm radiation, with tunability from 3.4 to 4.4 pm obtained by tuning the 2μm KTP OPO pump source while maintaining non-critical phase matching in the KTA OPO. The influence of pump beam quality upon optical parametric oscillator (OPO) performance is measured for both non-critical phase-matching, and OPOs with walkoff. Multimode OPO pumping is shown to be efficient, provided appropriate OPO cavities are employed. For low order pump modes, the OPO can be made to match the mode of the pump. Calculations of OPO efficiency for multimode pumping show fair agreement with experiment. Walkoff is shown to have a similar degrading effect upon efficiency to that caused by multimode pumping.

© 1994 Optical Society of America