Nonlinear propagation ofN intense waves: polarization states, refractive indices and self-focusing

Abstract

This paper presents a theoretical study of the nonlinear propagation ofN polarized intense waves in a macroscopically isotropic medium. General formulae are obtained for the polarization states and the nonlinear dependence of the index of refraction. In the absence of self-focusing, it is shown thatN linearly or circularly polarized waves retain their initial state of polarization during propagation. Results have been tabulated for the refractive indices and the polarization states ofN waves according to their initial polarization states. In the self-focusing regime, only circularly polarized waves conserve their polarization. This paper presents a description of the phenomenon of cross-focusing: in a certain power range, a wave of higher power induces self-focusing of a wave of lower power, whereas in some other situation, a stronger wave self-defocuses in the presence of a weak wave. In one of the situations, the phenomenon of an oscillatory waveguide is also exhibited. The polarization states of two waves in the self-focusing range have also been discussed.