Focusing Effect on Optical Parametric Oscillations for Three and Four Wave Interactions

Parametric gain, the oscillation condition, and output efficiency of optical parametric oscillator are considered. Both the resonant idler case and nonresonant idler case are taken into account with the resonator configuration of a plane and a spherical mirror. A matrix analysis is introduced for this consideration. The gain factor thus reduced is commonly used both for resonant idler and nonresonant idler case. The optimum focusing conditions for maximum gain are derived. The oscillation output power and efficiency are estimated analytically. This treatment is extended to the degenerate four wave interactions. The differences in gains due to the focusing condition and in output efficiencies are compared.