Spatio-Temporal Evolution Scenarios of Femtosecond Laser
Pulse Filamentation in Fused Silica
1

E. O. Smetanina*, A. E. Dormidonov, and V. P. Kandidov

Physics Department, Moscow State University, Moscow, 119991 Russia

*e-mail: smetanina@physics.msu.ru

Received November 30, 2011; in final form, December 21, 2011; published online June 12, 2012

Abstract—We investigated the evolution of femtosecond laser pulses at different wavelengths corresponding
to normal, zero, and anomalous regimes of group velocity dispersion (GVD) in fused silica. The laser pulse fil-
amentation in different GVD regimes under the same similarity parameters was first considered. It was estab-
lished numerically that the scenario of the pulse filamentation depends both on temporal factors, which are
determined by pulse GVD and self-phase modulation, and spatial factors associated with Kerr self-focusing and
plasma defocusing. In presence of strong normal GVD the dispersive stretching causes, a pulse power decrease
followed by lowering of the intensity in filament, electron density reduction in plasma channel, and suppressing
of the refocusing. For zero GVD the multipeak regime of radiation propagation is realized in the filament as a
result of recurring self-focusings of powerful pulse tail, which was defocused in laser plasma. When GVD is
anomalous a sequence of “light bullets” with duration about 10 fs forms in the filament. And the peak intensity
in “light bullet” stays the same 5 1013 W/cm2. In the regime of anomalous GVD power is transferred from
the pulse edges to its center, where the repeated self-focusings occur and form a “light bullet” sequence.

10.1134/S1054660X12070122


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