Terahertz-pulse emission through laser excitation of surface plasmons in a metal grating

G.H. Welsh, N.T. Hunt, K. Wynne

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The second-order processes of optical-rectification and photoconduction are well known and widely used to produce ultrafast electromagnetic pulses in the terahertz frequency domain. We present a new form of rectification that relies on the excitation of surface plasmons in metal films deposited on a shallow grating. Multiphoton ionization and ponderomotive acceleration of electrons in the enhanced evanescent field of the surface plasmons results in a femtosecond current surge and emission of terahertz electromagnetic radiation. Using gold, this rectification process is third or higher-order in the incident field.
Original languageEnglish
Article number026803
Number of pages4
JournalPhysical Review Letters
Issue number2
Publication statusPublished - 10 Jan 2007


  • optical-rectification
  • photoconduction
  • electromagnetic pulses
  • acceleration

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