Surface plasmon waves for broadband THz spectroscopy

Research output: Chapter in Book/Report/Conference proceedingConference contribution


  • O. Mitrofanov
  • R. Mueckstein
  • M. Natrella
  • C. Graham
  • C. C. Renaud
  • A. J. Seeds
  • F. Dominec
  • P. Kužel
  • J. C. Delagnes
  • P. Mounaix

Colleges, School and Institutes

External organisations

  • University College London
  • Academy of Sciences of Czech Republic
  • University of Bordeaux


In this presentation we discuss application of broadband terahertz (THz) time-domain spectroscopy for probing subwavelength (micrometer) size objects. The problem of weak coupling between THz waves and sub-wavelength objects, which limits the use of THz spectroscopy to large samples, is mitigated by employing surface plasmon waves. In one implementation, THz surface waves, excited on a broad-band planar THz bow-Tie antenna, are used to enhance the interaction with a small particle placed on the antenna surface. The surface field distribution near the particle is mapped with an integrated sub-wavelength aperture THz near-field probe. We demonstrate that imaging and probing of the subwavelength size dielectric particles (TiO2 and SrTiO3) can be realized using the enhanced THz field between the antenna and the probe. We also discuss THz wave confinement using two sharp metallic needles. We demonstrate that in the near-field region of the needle tips, the electric field of THz pulses is concentrated to a volume smaller than (10 μm)3 without limiting the THz pulse bandwidth. Application of both methods for high spatial resolution imaging and spectroscopy will be discussed..


Original languageEnglish
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
Publication statusPublished - 2014
EventQuantum Sensing and Nanophotonic Devices XI - San Francisco, CA, United States
Duration: 2 Feb 20146 Feb 2014


ConferenceQuantum Sensing and Nanophotonic Devices XI
CountryUnited States
CitySan Francisco, CA


  • near-field microscopy, plasmons, surface waves, terahertz, time-domain spectroscopy