Near-field phenomena observed with terahertz pulses

K. Wynne, J. Carey, J. Zawadzka, D.A. Jaroszynski

Research output: Contribution to conferencePaper

Abstract

Propagation of free-space femtosecond THz pulses (T rays) through and past metal structures with dimension on the order of a wavelength has been studied. In waveguides with diameters close to one wavelength, it is found that the phase velocity can become superluminal and even infinite or negative. T rays that propagate past a 100-micrometers metal wire are delayed when the polarization is perpendicular and advanced when it is parallel. In this case, it is also observed that the centroid velocity can become superluminal. Many of the result do not conform to simple waveguide theory, because of multiple reflections of the evanescent waves inside the waveguide. This 'Fabry-Perot' effect for evanescent waves is the cause of the negative phase velocities below the waveguide cutoff.
LanguageEnglish
Pages254-262
Number of pages8
Publication statusPublished - Jun 1999
EventTerahertz spectroscopy and applications 11 - Munich, Germany
Duration: 14 Jun 1999 → …

Conference

ConferenceTerahertz spectroscopy and applications 11
CityMunich, Germany
Period14/06/99 → …

Fingerprint

near fields
waveguides
evanescent waves
pulses
phase velocity
rays
wavelengths
metals
centroids
micrometers
cut-off
wire
propagation
causes
polarization

Keywords

  • ultrafast
  • imaging
  • wave propagation
  • terahertz
  • tunneling

Cite this

Wynne, K., Carey, J., Zawadzka, J., & Jaroszynski, D. A. (1999). Near-field phenomena observed with terahertz pulses. 254-262. Paper presented at Terahertz spectroscopy and applications 11, Munich, Germany, .
Wynne, K. ; Carey, J. ; Zawadzka, J. ; Jaroszynski, D.A. / Near-field phenomena observed with terahertz pulses. Paper presented at Terahertz spectroscopy and applications 11, Munich, Germany, .8 p.
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Wynne, K, Carey, J, Zawadzka, J & Jaroszynski, DA 1999, 'Near-field phenomena observed with terahertz pulses' Paper presented at Terahertz spectroscopy and applications 11, Munich, Germany, 14/06/99, pp. 254-262.

Near-field phenomena observed with terahertz pulses. / Wynne, K.; Carey, J.; Zawadzka, J.; Jaroszynski, D.A.

1999. 254-262 Paper presented at Terahertz spectroscopy and applications 11, Munich, Germany, .

Research output: Contribution to conferencePaper

TY - CONF

T1 - Near-field phenomena observed with terahertz pulses

AU - Wynne, K.

AU - Carey, J.

AU - Zawadzka, J.

AU - Jaroszynski, D.A.

PY - 1999/6

Y1 - 1999/6

N2 - Propagation of free-space femtosecond THz pulses (T rays) through and past metal structures with dimension on the order of a wavelength has been studied. In waveguides with diameters close to one wavelength, it is found that the phase velocity can become superluminal and even infinite or negative. T rays that propagate past a 100-micrometers metal wire are delayed when the polarization is perpendicular and advanced when it is parallel. In this case, it is also observed that the centroid velocity can become superluminal. Many of the result do not conform to simple waveguide theory, because of multiple reflections of the evanescent waves inside the waveguide. This 'Fabry-Perot' effect for evanescent waves is the cause of the negative phase velocities below the waveguide cutoff.

AB - Propagation of free-space femtosecond THz pulses (T rays) through and past metal structures with dimension on the order of a wavelength has been studied. In waveguides with diameters close to one wavelength, it is found that the phase velocity can become superluminal and even infinite or negative. T rays that propagate past a 100-micrometers metal wire are delayed when the polarization is perpendicular and advanced when it is parallel. In this case, it is also observed that the centroid velocity can become superluminal. Many of the result do not conform to simple waveguide theory, because of multiple reflections of the evanescent waves inside the waveguide. This 'Fabry-Perot' effect for evanescent waves is the cause of the negative phase velocities below the waveguide cutoff.

KW - ultrafast

KW - imaging

KW - wave propagation

KW - terahertz

KW - tunneling

UR - http://dx.doi.org/10.1117/12.361042

M3 - Paper

SP - 254

EP - 262

ER -

Wynne K, Carey J, Zawadzka J, Jaroszynski DA. Near-field phenomena observed with terahertz pulses. 1999. Paper presented at Terahertz spectroscopy and applications 11, Munich, Germany, .