Diffraction-Beam Optics of Filamentation: II–Diffraction-Beam Pattern of Laser Pulse Filamentation

Abstract

Based on the diffraction-ray representation of nonlinear propagation of laser pulses, some examples of visualization of the filamentation of high-power femtosecond laser pulses in air are considered in the form of evolutionary paths of diffraction beams and light tubes. It is ascertained that a filament is supported by the light energy of the part of the beam which is inside a beam tube with the initial peak power higher than the critical power of self-focusing. This light tube is an energy reservoir for the filament. The light beam periphery holds the diffraction-beam tube which includes the filament by means of formation of a “diffractive” waveguide.