Optical parametric oscillation with intracavity difference-frequency mixing

We report the theoretical analysis of an optical parametric oscillator that contains an intracavity crystal that generates the difference frequency between the signal and the idler produced by the optical parametric oscillator crystal. Phase mismatch in the difference-frequency mixer is considered. The cavity is singly resonant at the signal frequency. We find that high conversion efficiency of the difference and idler frequencies can be achieved over a large dynamic range of the incident pump intensity. A physical example that produces 3.192 μm from a 1.064-μm pump laser is predicted to produce 97.5% quantum efficiency in one polarization component and 197% quantum efficiency in the orthogonal-polarization component for a total power conversion efficiency of 98.2%.