A numerical solution for nanosecond single crystal upconversion optical parametric oscillators

Abstract

A model of single-crystal upconversion optical parametric oscillators (OPO’s) is a valuable tool for design and optimization. In these devices, a single nonlinear crystal is used both for optical parametric amplification (OPA) and sumfrequency/second-harmonic generation (SFG/SHG). This thesis presents a computational model for single-crystal upconversion OPO’s with pump pulse durations on the order of few nanoseconds. When the duration of the pump pulse is longer than the round trip time of the cavity used in the OPO, the transient nature of the problem must be taken into consideration. Besides the evolutions of the interacting light beams in time, the beam profiles and effects due to diffraction are incorporated into the model. Besides the model, incorporating nonlinear interaction and diffraction inside the crystal, solutions for different cavity components are given in detail. Computational results for a class-D sum-frequency OPO are presented, which are in good agreement with experimental measurements.