Dynamics of light structures during filamentation of femtosecond laser pulses in air

Abstract

A model of single filamentation of a high-power ultrashort light pulse has been developed on the basis of evolutionary dependencies of phase and amplitude parameters of the light field found from the numerical solution of a nonlinear Schrödinger equation for air. A key role of aberration and diffraction effects during the formation of localized stable dynamic light structures near the propagation axis is shown. It is found that the angular divergence of the postfilamentation light channel decreases with an increase in the laser beam radius at a fixed peak pulse power and is saturated when the radius is greater than 1 mm.