Beam quality characterization of nanosecond optical parametric oscillators

Summary form only given. We present a distinctive approach to the numerical modeling of pulsed nanosecond optical parametric oscillators (OPOs). Our model expands a recent procedure to the case of a nondegenerate, singly resonant OPO. A single partial differential equation describes the temporal and transverse variations of the resonated signal field and also accounts for diffraction, phase mismatching, and idler absorption. The model´s results can be compared with OPOs based on pulsed potassium titanyl phosphate or quasi-phase-matched materials, such as periodically poled lithium niobate where walk-off can be neglected. The numerical integration of our single-equation model is significantly faster than that of the corresponding three-coupled equations and enables the pump and idler fields to be reconstructed from the dynamics of the signal. Such speed of integration allows us to interpret the results of changes to input parameters in a matter of minutes.