Self-channeling of ultrashort laser pulses in materials with anomalous dispersion.
The nonlinear dynamics of femtosecond optical pulses propagating in solid media with anomalous group-velocity dispersion (GVD) is investigated. A map fixing the boundaries of collapse or noncollapse regimes for high-power beams versus the relative strength of GVD is first established. Next, from a nonlinear Schrödinger model accounting for higher-order dispersion, self-steepening, and plasma generation, the possibility of producing extended collapse events that promote a long self-guiding is confirmed, in agreement with recent experiments [K.D. Moll and A.L. Gaeta, Opt. Lett. 29, 995 (2004)]. Three-dimensional collapsing pulses are shown to propagate by emitting quasiperiodically bursts of temporally compressed light bullets, with durations close to the single cycle limit.
Bergé
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Département de Physique Théorique et Appliquée, CEA/DAM Ile de France, B.P. 12, 91680 Bruyères-le-Châtel, France.
Skupin
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