A recent experiment probing the electronic nonlinearity in the femtosecond filament indicated that the optical Kerr effect not only saturates but even changes its sign at high intensities and thus switches from self-focusing to a strongly defocusing regime. Here we examine, through simulations and experiment, some implications of such a behavior. We perform comparative simulations based on the standard model on one hand and on a model implementing the intensity-dependent Kerr effect on the other. Comparison with an experiment provides a strong indication that of these two Kerr-effect models the standard model is better in capturing the observed length of the filament. However, neither of the models can reproduce length and filament radius. Possible implications are discussed.
© 2010 Optical Society of America
Original Manuscript: August 10, 2010
Revised Manuscript: October 2, 2010
Manuscript Accepted: October 6, 2010
Published: October 28, 2010
Vol. 6, Iss. 1 Virtual Journal for Biomedical Optics
M. Kolesik, D. Mirell, J.-C. Diels, and J. V. Moloney, "On the higher-order Kerr effect in femtosecond filaments," Opt. Lett. 35, 3685-3687 (2010)