Parametric oscillation in KTP and KTA pumped at 1064 nm

We report the operation of an optical parametric oscillator (OPO) utilizing either potassium titanyl phosphate (KTP) or potassium titanyl arsenate (KTA) in a noncritically phase matched condition with the constraint of operation within a compact and ruggedized laser system. The design of a ruggedized OPO laser system presented some unique design requirements and are discussed. The discussions here deal solely with a fixed wavelength device. A comparison between KTP and KTA is given with regard to overall conversion efficiency and operational wavelength. Nominally identical crystals (size and surface coatings) of either material were utilized within the same resonator to give comparative data. We also report damage threshold values of KTP when used within an optical parametric oscillator. This data shows that the damage onset in these crystals is dependent on the parametric oscillation, and is not solely a function of the pump beam irradiance.