Optical parametric oscillator modeling with diffraction, depletion, and double refraction.

摘要

Advancement in the growth and fabrication of nonlinear materials along with continual improvements in the performance of solid-state lasers have led to a resurgence of interest in the development of optical parametric oscillators (OPOs). While many experimental results have been recently reported, very little attention has been given to the development of detailed models to simulate the output characteristics (such as beam quality, efficiency, and threshold) of nanosecond-pumped OPOs. Such models are necessary for understanding experiments and for developing advanced OPO designs that enhance the overall performance of these devices. In this work, we describe a time-dependent model of pulsed OPOs that includes diffraction, depletion, and double refraction (walkoff) in the parametric amplification process. The model is used to predict output beam profiles, beam quality, and conversion efficiency of an injection-seeded KTP ring OPO. Predicted output beam profiles in the near and intermediate fields are in qualitative agreement with the experimental results reports in a companion paper. Our results show that diffraction and double refraction must be included in models of pulsed OPOs to predict realistic beam profiles.