中国物理B ›› 2004, Vol. 13 ›› Issue (6): 905-912.doi: 10.1088/1009-1963/13/6/021

• PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES • 上一篇    下一篇

Chirping and spreading of ultrashort laser pulses in underdense plasmas

张秋菊, 盛政明, 张杰   

  1. Laboratory of Optical Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
  • 收稿日期:2003-05-16 修回日期:2004-02-02 出版日期:2005-07-05 发布日期:2005-07-05

Chirping and spreading of ultrashort laser pulses in underdense plasmas

Zhang Qiu-Ju (张秋菊), Sheng Zheng-Ming (盛政明), Zhang Jie (张杰)   

  1. Laboratory of Optical Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
  • Received:2003-05-16 Revised:2004-02-02 Online:2005-07-05 Published:2005-07-05

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摘要： A linear theory on the propagation of ultrashort pulses including only a few cycles in underdense plasmas is presented. It is shown that the dispersion in plasmas causes severe distortions in the pulse shape, including pulse chirping and spreading. The analytical calculations coincide very well with those obtained by particle-in-cell (PIC) simulations. The upper limit of the peak amplitude of the pulses, above which the linear theory breaks down due to the setting in of nonlinear effects of both the relativistic electron-mass increase and ponderomotive force, is also examined by PIC simulations. At certain high amplitudes, it is found that the ultrashort laser pulses can propagate like solitons.

Abstract: A linear theory on the propagation of ultrashort pulses including only a few cycles in underdense plasmas is presented. It is shown that the dispersion in plasmas causes severe distortions in the pulse shape, including pulse chirping and spreading. The analytical calculations coincide very well with those obtained by particle-in-cell (PIC) simulations. The upper limit of the peak amplitude of the pulses, above which the linear theory breaks down due to the setting in of nonlinear effects of both the relativistic electron-mass increase and ponderomotive force, is also examined by PIC simulations. At certain high amplitudes, it is found that the ultrashort laser pulses can propagate like solitons.

Key words: propagation, ultrashort laser pulse, plasma

中图分类号:  (Laser light absorption in plasmas (collisional, parametric, etc.))

  • 52.38.Dx
52.55.Dy (General theory and basic studies of plasma lifetime, particle and heat loss, energy balance, field structure, etc.) 42.60.Fc (Modulation, tuning, and mode locking) 42.65.Re (Ultrafast processes; optical pulse generation and pulse compression)