Initial phase modulation of a high-power femtosecond laser pulse as a tool for controlling its filamentation and generation of a supercontinuum in air

The possibility of controlling the processes of filamentation and generation of a supercontinuum during propagation of a high-power femtosecond laser pulse in air is investigated. Using a numerical simulation, it is shown that the initial phase modulation of the pulse results in a shift of the beginning of the filament from the output aperture of the laser system and in a significant increase in the filament length. The efficiency of the generation of the short-wavelength part of the supercontinuum in a pulse with a negative phase modulation is more than two orders of magnitude higher than for a pulse with a limited spectrum.