Femtosecond filamentation in air and higher-order nonlinearities

TL;DR

This paper investigates the role of higher-order nonlinearities in femtosecond filamentation in air, proposing a numerical experiment to distinguish between traditional and intensity-dependent Kerr-effect models, which could significantly impact understanding of filamentation.

Contribution

It introduces a numerical modeling approach to test the significance of higher-order nonlinearities in air filamentation, providing a method to discriminate between competing models.

Findings

Proposes an experiment to test nonlinear models in air filamentation.

Highlights the importance of higher-order nonlinearities in filamentation.

Suggests that intensity-dependent Kerr effects can alter filamentation dynamics.

Abstract

According to a recent experiment, the instantaneous electronic Kerr effect in air exhibits a strong intensity dependence, the nonlinear refractive index switching sign and crossing over from a self-focusing to a de-focusing nonlinearity. A subsequent theoretical work has demonstrated that this has paradigm-changing consequences for the understanding of filamentation in air, so it is important to subject the idea of higher-order nonlinearities to stringent tests. Here we use numerical modeling to propose an experiment capable of discriminating between the standard and the new intensity-dependent Kerr-effect models.