Beam Wander Restrained by Nonlinearity of Femtosecond Laser Filament in Air

Abstract

The filamentation process under atmospheric turbulence is critical to its remote-sensing application. The effects of turbulence intensity and location on the spatial distribution of femtosecond laser filaments in the air were studied. The experimental results show that the nonlinear effect of the filament can restrain the beam wander. When the turbulence intensity was 3.31×10−13 cm−2/3, the mean deviation of the wander of the filament center was only 27% of that of the linear transmitted beam. The change in turbulence location would lead to a change in the standard deviation of the beam centroid drift. Results also show that the filament length would be shortened, and that the filament would end up earlier in a turbulent environment. Since the filamentation-based LIDAR has been highly expected as an evolution multitrace pollutant remote-sensing technique, the study promotes our understanding of how turbulence influences filamentation and advances atmospheric remote sensing by applying a filament.

Femtosecond laser filamentation in simulated atmospheric turbulence [Invited]

“…Femtosecond laser filaments are inevitably affected by atmospheric turbulence in air, which poses an unavoidable problem for the practical application of femtosecond laser filaments. Recently, some studies have been reported on the effect of atmospheric turbulence on femtosecond laser filament formation [13,14] . Turbulence induces the fluctuation of the surrounding air density, consequently causing refractive index variations and distorting optical waves, which leads to a transverse stochastic distribution, increased filament counts, and expanded spot size [15][16][17] .…”