Large-aperture optical parametric oscillator with periodically poled KTiOPO/sub 4/

Summary form only given. Periodically poled ferroelectric crystals have been extensively used in nonlinear optical devices such as frequency doublers and optical parametric oscillators (OPOs) due to the large effective nonlinear coefficients, d/sub eff/, accessible through quasi-phase-matching and the possibility to engineer them for noncritical interaction. Primarily, the small apertures of available periodically poled crystals have imposed a limitation of the pulse energy that can be extracted using nanosecond pulses. In this work we report on the power scaling above 10 mJ in a singly resonant OPO realized with a 3-mm-thick periodically poled KTiOPO/sub 4/. We made a comparison of the OPO performance with several low repetition rate pump systems. The crystal behaves similarly for all these flash-lamp pump systems. The observed differences in saturated efficiency could be attributed to different intensity distributions of the pump beam. We also present results of the tuning of the signal and idler with temperature. An experimental investigation of the spatial qualities of the high-power parametric output, in the form of the M/sup 2/-value, is also given.