Focused terahertz waves generated by a phase velocity gradient in a parallel-plate waveguide

Robert W. McKinney, Yasuaki Monnai, Rajind Mendis, Daniel Mittleman

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

We demonstrate the focusing of a free-space THz beam emerging from a leaky parallel-plate waveguide (PPWG). Focusing is accomplished by grading the launch angle of the leaky wave using a PPWG with gradient plate separation. Inside the PPWG, the phase velocity of the guided TE1 mode exceeds the vacuum light speed, allowing the wave to leak into free space from a slit cut along the top plate. Since the leaky wave angle changes as the plate separation decreases, the beam divergence can be controlled by grading the plate separation along the propagation axis. We experimentally demonstrate focusing of the leaky wave at a selected location at frequencies of 100 GHz and 170 GHz, and compare our measurements with numerical simulations. The proposed concept can be valuable for implementing a flat and wide-aperture beam-former for THz communications systems.

Original languageEnglish
Pages (from-to)27947-27952
Number of pages6
JournalOptics Express
Volume23
Issue number21
DOIs
Publication statusPublished - 2015 Oct 19

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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