Kilometer-range nonlinear propagation of femtosecond laser pulses

Phys Rev E Stat Nonlin Soft Matter Phys. 2004 Mar;69(3 Pt 2):036607. doi: 10.1103/PhysRevE.69.036607. Epub 2004 Mar 30.

Abstract

Ultrashort, high-power laser pulses propagating vertically in the atmosphere have been observed over more than 20 km using an imaging 2-m astronomical telescope. This direct observation in several wavelength bands shows indications for filament formation at distances as far as 2 km in the atmosphere. Moreover, the beam divergence at 5 km altitude is smaller than expected, bearing evidence for whole-beam parallelization about the nonlinear focus. We discuss implications for white-light Lidar applications.