Nonlinear distortions of scanning light beams

The aberration-free approximation is used to analyze the propagation of Gaussian light beams which perform angular scanning in nonlinear defocustng and focusing media. Parametric solutions of the equations are obtained for the distortions of the Gaussian beam cross sections. The conditions are found under which thermal self-interactions are suppressed under fast scanning conditions. The effect of saturation of the angular deflection of a beam in a defocusing medium is studied in detail for the cases of fast and stow scanning. An asymptotic description of the process of propagation in a transparent layer is given. Various propagation regimes of a scanning beam (diffraction, pulsation, waveguide, and refraction) are established for a focusing medium.