Peculiarities of femtosecond laser beam filamentation in aerosol medium

The filamentation behavior of femtosecond laser pulses in air in the presence of aerosol on the optical path is simulated numerically on the base of (3D+1)-dimensional nonlinear Schrodinger equation. The effect of a localized attenuating layer modeling an aerosol medium extinction on the spatial extension and evolution of a light filament is investigated. It is shown for the first time that the filamentation length depends not only on the optical depth of the aerosol layer and pulse peak power but also on aerosol location on the propagation path. The length of the filament is maximal if the nonlinear focus of the beam is located behind the aerosol layer rather than before it.