中国物理B ›› 2013, Vol. 22 ›› Issue (10): 104207-104207.doi: 10.1088/1674-1056/22/10/104207

• ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS • 上一篇    下一篇

The dependence on optical energy of terahertz emission from air plasma induced by two-color femtosecond laser-pulses

吴四清a b, 刘劲松a, 汪盛烈a, 胡兵a   

  1. a Wuhan National Laboratory for Optoelectronics,School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China;
    b School of Electronic and Information Engineering, Hubei University of Science & Technology, Xianning 437100, China
  • 收稿日期:2013-03-27 修回日期:2013-04-08 出版日期:2013-08-30 发布日期:2013-08-30
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 61177095), the Natural Science Foundation of Hubei Province, China (Grant No. 2012FFA074), the Ph. D. Programs Foundation of Ministry of Education of China (Grant No. 20100142110042), and the Fundamental Research Funds for the Central Universities (Grant Nos. 2012QN094 and 2012QN097).

The dependence on optical energy of terahertz emission from air plasma induced by two-color femtosecond laser-pulses

Wu Si-Qing (吴四清)a b, Liu Jin-Song (刘劲松)a, Wang Sheng-Lie (汪盛烈)a, Hu Bing (胡兵)a   

  1. a Wuhan National Laboratory for Optoelectronics,School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China;
    b School of Electronic and Information Engineering, Hubei University of Science & Technology, Xianning 437100, China
  • Received:2013-03-27 Revised:2013-04-08 Online:2013-08-30 Published:2013-08-30
  • Contact: Liu Jin-Song E-mail:jsliu4508@vip.sina.com
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 61177095), the Natural Science Foundation of Hubei Province, China (Grant No. 2012FFA074), the Ph. D. Programs Foundation of Ministry of Education of China (Grant No. 20100142110042), and the Fundamental Research Funds for the Central Universities (Grant Nos. 2012QN094 and 2012QN097).

摘要: The generation of terahertz (THz) emission from air plasma induced by two-color femtosecond laser pulses is studied on the basis of a transient photocurrent model. While the gas is ionized by the two-color femtosecond laser-pulses composed of the fundamental and its second harmonic, a non-vanishing directional photoelectron current emerges, radiating a THz electromagnetic pulse. The gas ionization processes at three different laser-pulse energies are simulated, and the corresponding THz waveforms and spectra are plotted. The results demonstrate that, by keeping the laser-pulse width and the relative phase between two pulses invariant when the laser energy is at a moderate value, the emitted THz fields are significantly enhanced with a near-linear dependence on the optical energy.

关键词: terahertz emission, air plasma, femtosecond laser-pulses

Abstract: The generation of terahertz (THz) emission from air plasma induced by two-color femtosecond laser pulses is studied on the basis of a transient photocurrent model. While the gas is ionized by the two-color femtosecond laser-pulses composed of the fundamental and its second harmonic, a non-vanishing directional photoelectron current emerges, radiating a THz electromagnetic pulse. The gas ionization processes at three different laser-pulse energies are simulated, and the corresponding THz waveforms and spectra are plotted. The results demonstrate that, by keeping the laser-pulse width and the relative phase between two pulses invariant when the laser energy is at a moderate value, the emitted THz fields are significantly enhanced with a near-linear dependence on the optical energy.

Key words: terahertz emission, air plasma, femtosecond laser-pulses

中图分类号:  (Laser spectroscopy)

  • 42.62.Fi
42.65.Re (Ultrafast processes; optical pulse generation and pulse compression) 52.38.Dx (Laser light absorption in plasmas (collisional, parametric, etc.)) 52.25.Jm (Ionization of plasmas)