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arXiv · 1411.4914

Sensitivity of propagation and energy deposition in femtosecond filamentation to the nonlinear refractive index

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

The axial dependence of femtosecond filamentation in air is measured under conditions of varying laser pulsewidth, energy, and focusing f-number. Filaments are characterized by the ultrafast z-dependent absorption of energy from the laser pulse and diagnosed by measuring the local single cycle acoustic wave generated. Results are compared to 2D+1 simulations of pulse propagation, whose results are highly sensitive to the instantaneous (electronic) part of the nonlinear response of $N_2$ and $O_2$. We find that recent measurements of the nonlinear refractive index ($n_2$) in [J.K. Wahlstrand et al., Phys. Rev. A. 85, 043820 (2012)] provide the best match and an excellent fit between experiments and simulations.

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E. W. Rosenthal, J. P. Palastro, N. Jhajj, S. Zahedpour, J. K. Wahlstrand, H. M. Milchberg. 2014-11-18. Sensitivity of propagation and energy deposition in femtosecond filamentation to the nonlinear refractive index. https://doi.org/10.1088/0953-4075%2F48%2F9%2F094011

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