Frequency-dependent radiation patterns emitted by THz plasmons on finite length cylindrical metal wires.

Autor: Deibel JA, Berndsen N, Wang K, Mittleman DM, van der Valk NC, Planken PC
Jazyk: angličtina
Zdroj: Optics express [Opt Express] 2006 Sep 18; Vol. 14 (19), pp. 8772-8.
DOI: 10.1364/oe.14.008772
Abstrakt: We report on the emission patterns from THz plasmons propagating towards the end of cylindrical metal waveguides. Such waveguides exhibit low loss and dispersion, but little is known about the dynamics of the terahertz radiation at the end of the waveguide, specifically in the near- and intermediate-field. Our experimental results and numerical simulations show that the near- and intermediate-field terahertz spectra, measured at the end of the waveguide, vary with the position relative to the waveguide. This is explained by the frequency-dependent diffraction occurring at the end of the cylindrical waveguide. Our results show that near-field changes in the frequency content of THz pulses for increasing wire-detector distances must be taken into account when studying surface waves on cylindrical waveguides.
Databáze: MEDLINE