Filamentation of powerful frequency-modulated femtosecond laser pulse on a vertical path in the atmosphere

摘要

The possibility of chirped laser pulses application for "high-altitude" light filament generation during propagation of the high-power femtosecond radiation on vertical atmospheric path taking into account the changing of a nonlinear interactions constants versus altitude. It is shown on the basis of the model of barometrical reduction of the air density and corresponding increase of the critical self-focusing power we can really operate the nonlinear beam focus location using chirping. The pulse without frequency modulation propagates on th path in linear regime without filament forming and chirping of such pulse leads to its temporal compression and as a result to light filament formation with high peak intensity.