The Effect of Turbulence on Generation of High-Intensity Light Channels during Femtosecond Laser Pulse Propagation along a 100-Meter Air Path

Abstract

Remote control of high-intensity laser beams in the atmosphere is an important problem of atmospheric optics. It is of special interest for atmospheric sounding, where turbulence can affect beam propagation. We experimentally study the effect of a turbulent layer produced at the beginning of a laser radiation propagation path on the characteristics of the filamentation domain and generation of high-intensity plasma-free channels for laser beams 2.5 and 5 cm diameter, including under the phase control of the transverse beam structure with a deformable mirror. In the presence of turbulence, the beginning of multiple filamentation domain approaches, however, insignificantly (<10% of the path length), a radiation source. More important is that a turbulent layer formed at the beginning of a path results in a multiple increase in the number of high-intensity (mean intensity is ∼10¹¹–10¹² W/cm²) light channels in a laser beam during its nonlinear propagation, which induce two-photon fluorescence of dyes at a distance of longer than 100 m from the radiation source with the signal level sufficient for its recording by a lidar scheme. This laser beam structure can be used for sounding natural and anthropogenic aerosols.