Generation of radially-polarized terahertz pulses for coupling into coaxial waveguides

Research output: Contribution to journalArticle

Authors

Colleges, School and Institutes

Abstract

Coaxial waveguides exhibit no dispersion and therefore can serve as an ideal channel for transmission of broadband THz pulses. Implementation of THz coaxial waveguide systems however requires THz beams with radially-polarized distribution. We demonstrate the launching of THz pulses into coaxial waveguides using the effect of THz pulse generation at semiconductor surfaces. We find that the radial transient photo-currents produced upon optical excitation of the surface at normal incidence radiate a THz pulse with the field distribution matching the mode of the coaxial waveguide. In this simple scheme, the optical excitation beam diameter controls the spatial profile of the generated radially-polarized THz pulse and allows us to achieve efficient coupling into the TEM waveguide mode in a hollow coaxial THz waveguide. The TEM quasi-single mode THz waveguide excitation and non-dispersive propagation of a short THz pulse is verified experimentally by time-resolved near-field mapping of the THz field at the waveguide output.

Details

Original languageEnglish
Article number38926
JournalScientific Reports
Volume6
Publication statusPublished - 12 Dec 2016

Keywords

  • Ultrafast photonics, Electrical and electronic engineering, Semiconductors, Terahertz optics