Mixing of polarization states in zincblende nonlinear optical crystals

We describe second-order nonlinear optical mixing in non-birefringent, zincblende-structure materials that can be quasi-phasematched. Lack of birefringence and quasi-phasematching together allow efficient nonlinear mixing between diverse polarization states. We derive six coupled-wave equations that describe nonlinear optical mixing between the two orthogonal polarizations of the three frequencies in the second-order nonlinear interaction. The interactions of the additional polarization states can lead to apparent reduction in conversion efficiencies in optical parametric oscillators and amplifiers.