Strong terahertz emission from electromagnetic diffusion near cutoff in plasma

M-H Cho, Y-K Kim, H Suk, B Ersfeld, D A Jaroszynski, M S Hur

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A new mechanism for electromagnetic emission in the terahertz (THz) frequency regime from laser-plasma interactions is described. A localized and long-lasting transverse current is produced by two counter-propagating short laser pulses in weakly magnetized plasma.We show that the electromagnetic wave radiating from this current source, even though its frequency is close to cut-off of the ambient plasma, grows and diffuses towards the plasma-vacuum boundary, emitting a strong monochromatic THz wave. With driving laser pulses of moderate power, the THz wave has a field strength of tens of MVm−1, a frequency of a few THz and a quasi-continuous power that exceeds all previous monochromatic THz sources. The novelty of the mechanism lies in a diffusing electromagnetic wave close to cut-off, which is modelled by a continuously driven complex diffusion equation.
Original languageEnglish
Article number043045
Number of pages8
JournalNew Journal of Physics
Issue number4
Publication statusPublished - 22 Apr 2015


  • laser-plasma
  • terahertz radiation
  • laser wakefield

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