WIAS Preprint No. 1627, (2011)

Directionality of THz emission from photoinduced gas plasmas


  • Köhler, Christian
  • Cabrera-Granado, Eduardo
  • Babushkin, Ihar
  • Bergé, Luc
  • Herrmann, Joachim
  • Skupin, Stefan

2010 Mathematics Subject Classification

  • 35Q60 78A60 76X05


  • THz emission, photoinduced plasma, nonlinear optics




Forward and backward THz emission by ionizing two-color laser pulses in gas is investigated by means of a simple semi-analytical model based on Jefimenko's equation and rigorous Maxwell simulations in one and two dimensions. We find the emission in backward direction having a much smaller spectral bandwidth than in forward direction and explain this by interference effects. Forward THz radiation is generated predominantly at the ionization front and is thus almost not affected by the opacity of the plasma, in excellent agreement with results obtained from a unidirectional pulse propagation model.

Appeared in

  • Optics Letters, 36 (2011) pp. 3166--3168.

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