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arXiv · 1401.1495

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

J. K. Wahlstrand·N. Jhajj·E. W. Rosenthal·S. Zahedpour·H. M. Milchberg
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Abstract

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.

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J. K. Wahlstrand, N. Jhajj, E. W. Rosenthal, S. Zahedpour, H. M. Milchberg. 2014-01-07. Direct measurement of the acoustic waves generated by femtosecond filaments in air. https://doi.org/10.1364/ol.39.001290

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