The terahertz(THz)temporal waveform and spectrum from a longitudinal electrically biased femtosecond filament is studied experimentally.The initial direction of the electron motion inside the unbiased filament plasma ...The terahertz(THz)temporal waveform and spectrum from a longitudinal electrically biased femtosecond filament is studied experimentally.The initial direction of the electron motion inside the unbiased filament plasma is deduced from the transformation of the THz temporal waveform with applied fields of opposite polarities.Furthermore,a spectrum shift to lower frequency of the THz spectrum is observed in the presence of a biased field.It agrees well with theoretical predictions.展开更多
基金Supported by the National Natural Science Foundation of China(Grant No.11574213)the Innovation Program of Shanghai Municipal Education Commission(Grant No.2017–01-07-00-07-E00007)。
文摘The terahertz(THz)temporal waveform and spectrum from a longitudinal electrically biased femtosecond filament is studied experimentally.The initial direction of the electron motion inside the unbiased filament plasma is deduced from the transformation of the THz temporal waveform with applied fields of opposite polarities.Furthermore,a spectrum shift to lower frequency of the THz spectrum is observed in the presence of a biased field.It agrees well with theoretical predictions.