Laser filamentation is understood to be self-channeling of intense ultrashort laser pulses achieved when the self-focusing because of the Kerr nonlinearity is balanced by ionization-induced defocusing. Here, we show that, right behind the ionized region of a laser filament, ultrashort laser pulses can couple into a much longer light channel, where a stable self-guiding spatial mode is sustained by the saturable self-focusing nonlinearity. In the limiting regime of negligibly low ionization, this post-filamentation beam dynamics converges to a large-scale beam self-trapping scenario known since the pioneering work on saturable self-focusing nonlinearities.
© 2014 Optical Society of America
Original Manuscript: May 20, 2014
Revised Manuscript: June 18, 2014
Manuscript Accepted: June 23, 2014
Published: August 5, 2014
A. V. Mitrofanov, A. A. Voronin, D. A. Sidorov-Biryukov, G. Andriukaitis, T. Flöry, A. Pugžlys, A. B. Fedotov, J. M. Mikhailova, V. Ya. Panchenko, A. Baltuška, and A. M. Zheltikov, "Post-filament self-trapping of ultrashort laser pulses," Opt. Lett. 39, 4659-4662 (2014)