Vol. 4, issue 10, article # 5

Abstract:

An analytical solution of the radiation transfer equation is constructed in the space of Lagrangian variables spatially related to three–dimensional trajectories of optical rays. Using this solution the parabolic equation for the wave eikonal is reduced to a system of five ordinary differential equations. This system of equations describes the lowest–order aberrational distortions of noncircular beams with axial symmetry in media with an arbitrary mechanism of nonlinearity. To illustrate the efficiency of the obtained system the nonlinear part of the dielectric constant of media with the Kerr and thermal types of nonlinearity has been calculated. Evolutions of wave aberrations of axially symmetric beams in both types of nonlinear media are compared.