<title>Damage thresholds of nonlinear crystals used for optical parametric oscillators <emph type="3">(Abstract Only)</emph></title>

We report damage threshold results for potassium titanyl phosphate (KTP) and potassium titanyl arsenate (KTA) which are cut for use as nonlinear crystals in noncritically phase matched optical parametric oscillators. Controlled experiments are described that shed light on the damage process in these nonlinear crystals in terms of the pump, signal, and idler wavelengths. Both surface and bulk material damage morphology is described for each crystal type and for each wavelength. Both materials were evaluated with our optical parametric oscillator damage test facility, which operates at a wavelength of 1574 nm and our Q-switched Nd:YAG test facility that operates at a wavelength of 1064 nm. A comparison of the relative merits of these crystal types as OPO materials is also given.