Influence of Initial Amplitude Perturbations on Filament Length of Pre-focused Femtosecond Laser Pulses

摘要

Influence of random initial amplitude perturbations on the filamentation of prefocused femtosecond laser pulses is numerically studied.Simulations are performed for the filamentation of laser pulses with different modulation degrees and initial geometric focusings.The transverse waist of the laser beam is 5 mm.The behavior of the filament is strongly affected by the initial non-uniformity of the laser pulse envelope for a short initial focal length(f=1 m).In this case,the filament and plasma channel can survive for a longer distance with a small initial amplitude perturbation.For a laser pulse focused by a lens with a long focal length(f=4 m),decrease in the initial perturbation does not contribute to the length of the filament and the plasma channel.