中国物理B ›› 2015, Vol. 24 ›› Issue (11): 114207-114207.doi: 10.1088/1674-1056/24/11/114207

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Defocusing role in femtosecond filamentation: Higher-order Kerr effect or plasma effect?

李苏宇a b, 郭福明a b, 杨玉军a b, 金明星a b   

  1. a Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China;
    b Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University), Changchun 130012, China
  • 收稿日期:2015-07-01 修回日期:2015-07-29 出版日期:2015-11-05 发布日期:2015-11-05
  • 通讯作者: Jin Ming-Xing E-mail:mxjin@jlu.edu.cn
  • 基金资助:
    Project supported by the National Basic Research Program of China (Grant No. 2013CB922200), the National Natural Science Foundation of China (Grant Nos. 11034003 and 11474129), the Research Fund for the Doctoral Program of Higher Education in China (Grant No. 20130061110021), and the Graduate Innovation Fund of Jilin University, China (Grant No. 2015091).

Defocusing role in femtosecond filamentation: Higher-order Kerr effect or plasma effect?

Li Su-Yu (李苏宇)a b, Guo Fu-Ming (郭福明)a b, Yang Yu-Jun (杨玉军)a b, Jin Ming-Xing (金明星)a b   

  1. a Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China;
    b Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University), Changchun 130012, China
  • Received:2015-07-01 Revised:2015-07-29 Online:2015-11-05 Published:2015-11-05
  • Contact: Jin Ming-Xing E-mail:mxjin@jlu.edu.cn
  • Supported by:
    Project supported by the National Basic Research Program of China (Grant No. 2013CB922200), the National Natural Science Foundation of China (Grant Nos. 11034003 and 11474129), the Research Fund for the Doctoral Program of Higher Education in China (Grant No. 20130061110021), and the Graduate Innovation Fund of Jilin University, China (Grant No. 2015091).

摘要: The femtosecond filamentation in the classical and high-order Kerr (HOK) models is numerically investigated by adopting multi-photon ionization (MPI) cross section with different values. It is found that in the case that the MPI cross section is relatively small, there exists a big difference between the electron density as well as clamped intensity calculated in the classical model and those calculated in the HOK one, while in the case that the MPI cross section is relatively large, the electron density and clamped intensity calculated in the two models are nearly in agreement with each other, and under this circumstance, even if the higher-order nonlinear terms do exist, the free-charge generation and the associated defocusing in a filament are enough to mask their effects. The different behaviors of the maximum intensity and on-axis electron density at the collapse position with the pulse duration provides an approach to determine which effect plays the dominant defocusing role. These results demonstrate that it is ionization that results in the difference between the two models.

关键词: high-order Kerr model, plasma defocusing, filamentation

Abstract: The femtosecond filamentation in the classical and high-order Kerr (HOK) models is numerically investigated by adopting multi-photon ionization (MPI) cross section with different values. It is found that in the case that the MPI cross section is relatively small, there exists a big difference between the electron density as well as clamped intensity calculated in the classical model and those calculated in the HOK one, while in the case that the MPI cross section is relatively large, the electron density and clamped intensity calculated in the two models are nearly in agreement with each other, and under this circumstance, even if the higher-order nonlinear terms do exist, the free-charge generation and the associated defocusing in a filament are enough to mask their effects. The different behaviors of the maximum intensity and on-axis electron density at the collapse position with the pulse duration provides an approach to determine which effect plays the dominant defocusing role. These results demonstrate that it is ionization that results in the difference between the two models.

Key words: high-order Kerr model, plasma defocusing, filamentation

中图分类号:  (Beam trapping, self-focusing and defocusing; self-phase modulation)

  • 42.65.Jx
42.65.Re (Ultrafast processes; optical pulse generation and pulse compression) 52.35.Mw (Nonlinear phenomena: waves, wave propagation, and other interactions (including parametric effects, mode coupling, ponderomotive effects, etc.)) 42.65.Tg (Optical solitons; nonlinear guided waves)