Simultaneous nonlinear conversion of light in periodically poled crystals

We consider a nondegenerate parametric process ω₃ → ω₁ + ω₂ and simultaneous sum frequency generation ω₁ + ω₃ → ω₄ and ω₂ + ω₃ → ω₅ in periodically poled quadratic crystals. An algorithm is proposed for the numerical description of the system evolution with full allowance for the quantum-mechanical interaction of all five plane monochromatic modes and pump depletion. The behaviour of the average number of photons of interacting modes and their mutual correlations is studied. An effect of inversion of the mutual correlation of the modes of the generated light is found.