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Terahertz focusing and polarization control in large-area bias-free semiconductor emitters

Terahertz focusing and polarization control in large-area bias-free semiconductor emitters
Terahertz focusing and polarization control in large-area bias-free semiconductor emitters

We show that, when large-area multiplex terahertz semiconductor emitters, that work on diffusion currents and Schottky potentials, are illuminated by ultrashort optical pulses they can radiate a directional electromagnetic terahertz pulse which is controlled by the angular spectrum of the incident optical beam. Using the lens that focuses the incident near-infrared pulse, we have demonstrated THz emission focusing in free space, at the same point where the optical radiation would focus. We investigated the beam waist and Gouy phase shift of the THz emission as a function of frequency. We also show that the polarization profile of the emitted THz can be tailored by the metallic patterning on the semiconductor, demonstrating radial polarization when a circular emitter design is used. Our techniques can be used for fast THz beam steering and mode control for efficiently coupling to waveguides without the need for THz lenses or parabolic mirrors.

Spectroscopy, Terahertz, Ultrafast lasers
1866-6892
223–235
Carthy, Joanna L.
75c5d2a0-bba4-4d94-a53d-76d4a2680125
Gow, Paul C.
193394b1-fe2d-41de-a9aa-6de7e5925b18
Berry, Sam A.
0f768f48-36c4-4599-8917-7aae657378a7
Mills, Ben
05f1886e-96ef-420f-b856-4115f4ab36d0
Apostolopoulos, Vasilis
8a898740-4c71-4040-a577-9b9d70530b4d
Carthy, Joanna L.
75c5d2a0-bba4-4d94-a53d-76d4a2680125
Gow, Paul C.
193394b1-fe2d-41de-a9aa-6de7e5925b18
Berry, Sam A.
0f768f48-36c4-4599-8917-7aae657378a7
Mills, Ben
05f1886e-96ef-420f-b856-4115f4ab36d0
Apostolopoulos, Vasilis
8a898740-4c71-4040-a577-9b9d70530b4d

Carthy, Joanna L., Gow, Paul C., Berry, Sam A., Mills, Ben and Apostolopoulos, Vasilis (2018) Terahertz focusing and polarization control in large-area bias-free semiconductor emitters. JOURNAL OF INFRARED MILLIMETER AND TERAHERTZ WAVES, 39 (3), 223–235. (doi:10.1007/s10762-017-0452-4).

Record type: Article

Abstract

We show that, when large-area multiplex terahertz semiconductor emitters, that work on diffusion currents and Schottky potentials, are illuminated by ultrashort optical pulses they can radiate a directional electromagnetic terahertz pulse which is controlled by the angular spectrum of the incident optical beam. Using the lens that focuses the incident near-infrared pulse, we have demonstrated THz emission focusing in free space, at the same point where the optical radiation would focus. We investigated the beam waist and Gouy phase shift of the THz emission as a function of frequency. We also show that the polarization profile of the emitted THz can be tailored by the metallic patterning on the semiconductor, demonstrating radial polarization when a circular emitter design is used. Our techniques can be used for fast THz beam steering and mode control for efficiently coupling to waveguides without the need for THz lenses or parabolic mirrors.

Text
10.1007-s10762-017-0452-4 - Version of Record
Available under License Creative Commons Attribution.
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Accepted/In Press date: 25 November 2017
e-pub ahead of print date: 25 November 2017
Published date: March 2018
Keywords: Spectroscopy, Terahertz, Ultrafast lasers

Identifiers

Local EPrints ID: 416676
URI: https://eprints.soton.ac.uk/id/eprint/416676
ISSN: 1866-6892
PURE UUID: f3e1639f-6f2b-4ecb-95cd-bf75fed8e5c5
ORCID for Paul C. Gow: ORCID iD orcid.org/0000-0002-3247-9082
ORCID for Sam A. Berry: ORCID iD orcid.org/0000-0002-9538-8655
ORCID for Ben Mills: ORCID iD orcid.org/0000-0002-1784-1012
ORCID for Vasilis Apostolopoulos: ORCID iD orcid.org/0000-0003-3733-2191

Catalogue record

Date deposited: 04 Jan 2018 17:30
Last modified: 18 May 2019 00:33

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Contributors

Author: Joanna L. Carthy
Author: Paul C. Gow ORCID iD
Author: Sam A. Berry ORCID iD
Author: Ben Mills ORCID iD

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