title: Femtosecond filamentation in argon and higher-order nonlinearities.
abstract: We numerically investigate the femtosecond filamentation dynamics in argon by considering the higher-order nonlinearities measured by a recent experiment. Our result indicates that, instead of plasma, these higher-order nonlinearities can provide main defocusing effect as shown by a recent theoretical work. However, when the higher-order nonlinearity is so strong to provide a main defocusing effect, some phenomena inconsistent with previous experiments such as pulse splitting and pulse self-compression can appear. Therefore, we infer that the values of higher-order nonlinear coefficients are overestimated, and the plasma should be the defocusing mechanism at least in the argon filament.
authors.affiliation: School of Physics and Electronic Engineering, Xuzhou Normal University, Xuzhou 221116, China.
authors.forename: Zhanxin
authors.initials: Z
authors.lastname: Wang
authors.forename: Chaojin
authors.initials: C
authors.lastname: Zhang
authors.forename: Jiansheng
authors.initials: J
authors.lastname: Liu
authors.forename: Ruxin
authors.initials: R
authors.lastname: Li
authors.forename: Zhizhan
authors.initials: Z
authors.lastname: Xu