%0 Journal Article
%T Direct measurement of the acoustic waves generated by femtosecond filaments in air
%A J. K. Wahlstrand
%A N. Jhajj
%A E. W. Rosenthal
%A S. Zahedpour
%A H. M. Milchberg
%J Physics
%D 2014
%I arXiv
%R 10.1364/OL.39.001290
%X We present direct measurements of the gas acoustic dynamics following interaction of spatial single- and multi-mode 50 fs, 800 nm pulses in air at 10 Hz and 1 kHz repetition rates. Results are in excellent agreement with hydrodynamic simulations. Under no conditions for single filaments do we find on-axis enhancement of gas density; this occurs only with multi-filaments. We also investigate the propagation of probe beams in the gas density profile induced by a single extended filament. We find that light trapping in the expanding annular acoustic wave can create the impression of on-axis guiding in a limited temporal window.
%U http://arxiv.org/abs/1401.1495v1