Phase-Insensitive Scattering of Terahertz Radiation
1
School of Engineering and Physical Sciences, SUPA, Heriot-Watt University, Edinburgh EH14 4AS, UK
2
Max Planck Institute for the Science of Light (MPL), D-91058 Erlangen, Germany
3
Department of Physics and Solid State Institute, Technion, Haifa 32000, Israel
4
Centre de Physique Théorique CNRS, École Polytechnique, F-91128 Palaiseau, France
5
INRS-EMT, 1650 Blvd. Lionel-Boulet, Varennes, QC J3X 1S2, Canada
6
Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, China
7
National Research University of Information Technologies, Mechanics and Optics, St. Petersburg 197101, Russia
8
School of Engineering, University of Glasgow, Glasgow G12 8LT, UK
*
Authors to whom correspondence should be addressed.
Photonics 2017, 4(1), 7; https://doi.org/10.3390/photonics4010007
Received: 17 November 2016 / Accepted: 25 January 2017 / Published: 31 January 2017
(This article belongs to the Special Issue Ultrafast Photonics and Attosecond Sciences)
The nonlinear interaction between Near-Infrared (NIR) and Terahertz pulses is principally investigated as a means for the detection of radiation in the hardly accessible THz spectral region. Most studies have targeted second-order nonlinear processes, given their higher efficiencies, and only a limited number have addressed third-order nonlinear interactions, mainly investigating four-wave mixing in air for broadband THz detection. We have studied the nonlinear interaction between THz and NIR pulses in solid-state media (specifically diamond), and we show how the former can be frequency-shifted up to UV frequencies by the scattering from the nonlinear polarisation induced by the latter. Such UV emission differs from the well-known electric field-induced second harmonic (EFISH) one, as it is generated via a phase-insensitive scattering, rather than a sum- or difference-frequency four-wave-mixing process.
Keywords:
terahertz; ultrafast photonics; nonlinear optics