Influence of the statistical and spatio-temporal features of laser pulse on its depolarization in a Kerr medium

Due to nonlinear rotation of polarization, the stochastic intensity and the spatio-temporal inhomogeneity of a multimode laser beam results to its depolarization when propagating in a nonlinear media. The ensemble and spatio-temporal averaging of Stokes parameters was performed analytically for an isotropic media and numerically for an anisotropic one. The experimentally measurable Stokes parameters show monotonic or oscillating decreasing dependence on the propagation distance; the characteristic depolarization length is evaluated. With respect to depolarization the anisotropic media is shown to behave like the isotropic one if the radiation intensity is sufficiently high. The measured value of depolarization agrees with the presented calculations.