Dynamic chaos in the case of parametric interactions of light waves

An investigation is made of the spatial evolution of a system of constant-frequency light waves, each of which participates in two four-wave parametric interaction processes simultaneously. It is shown that the competition between the parametric processes may result in spatial chaos. The chaotic evolution regime is established if the wave amplitudes at the boundary of a nonlinear medium differ sufficiently from the values corresponding to an integrable limit, the existence of which depends on the symmetry of the system. The other condition for the appearance of chaos—strong interwave energy exchange—is obeyed when the parameters of the medium and of the radiation are of the same orders of magnitude as in the case of reflection accompanied by amplification in phase conjugation of a laser radiation wavefront on the basis of a degenerate four-wave mixing. The characteristic features of the appearance of a stochastic instability of a system of interacting light waves under experimental conditions are considered.