Comparison of continuous-wave optical parametric oscillators based on periodically poled LiNbO_3 and periodically poled RbTiOAsO_4 pumped internal to a high-power Nd:YVO_4 laser

We present and compare two continuous-wave optical parametric oscillators based on the nonlinear crystals periodically poled LiNbO3 (PPLN) and periodically poled RbTiOAsO4 (PPRTA) pumped internal to a high-power, all-solid-state Nd:YVO4 laser. At a diode pump power of 12 W, similar total extracted idler powers of over 440 mW were obtained from each system even though the nonlinearity of PPRTA is significantly less than that of PPLN. The spatial, power, and frequency stability of the PPRTA-based system outperformed those of the PPLN system. We attribute the poor performance of PPLN in these parameters to its susceptibility to thermal lensing.