Vol. 18, issue 10, article # 4

Abstract:

A possibility of application of laser chirps to creation of an "altitude" light filament with accounting for altitude variation of nonlinear interaction constants in the case of high-power femtosecond radiation propagation along vertical atmospheric paths is under discussion. Based on the model of exponential decrease in air density and the corresponding increase in the self-focusing critical power, it is shown that position of the nonlinear beam focus can be under control with the use of chirping. At the same time, pulses free of frequency modulation propagate along the path linearly and the filament does not appear; while chirping such pulses leads to their provisional compression, and, as a result, to formation of a light filament of high peak intensity.