Direct imaging of the acoustic waves generated by femtosecond filaments in air

J. K. Wahlstrand, N. Jhajj, E. W. Rosenthal, S. Zahedpour, H. M. Milchberg
2014 Optics Letters  
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
more » ... hat light trapping in the expanding annular acoustic wave can create the impression of on-axis guiding in a limited temporal window.
doi:10.1364/ol.39.001290 pmid:24690729 fatcat:lbnx5kdl6ff2nhuje7z3dedh74