Cluster selection in doubly-resonant OPOs based on quasi-phase-matched materials

Summary form only given. Doubly-resonant OPOs (DROs) are attractive for their low thresholds. This is especially important in the case of diode-laser pumping where available power is usually limited and further reductions in threshold are often made by the use of quasi-phase-matched materials such as PPLN. We have carried out an analysis which attributes this behavior to several clusters falling within the phase-matching bandwidth of the material and therefore having similar thresholds. The results of our study indicate that a phase-matching bandwidth much larger than the cluster spacing is common to many demonstrated, or potential, QPM materials pumped at near-infrared wavelengths due to their largely similar dispersive properties The results of our analysis are presented and the implications for diode-pumped DROs using QPM materials, and potential solutions to the problem, are discussed.