Multiple filamentation of laser beams of different diameters in air along a 150-meter path

Abstract

Results of experiments on controlling the position and length of the filamentation region of femtosecond laser pulses along atmospheric paths 150 m long using different initial spatial focusing and defocusing are presented. The distribution of filaments over the filamentation region is found; the dependencies of the length of the filamentation region on the numerical aperture of a beam, its initial radius, and pulse power are derived. Emission spectra of targets made of different materials and placed in the filamentation region far from the radiation source are measured.