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Compact terahertz harmonic generation in the Reststrahlenband using a graphene-embedded metallic split ring resonator array.

Published version
Peer-reviewed

Repository DOI


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Authors

Di Gaspare, Alessandra  ORCID logo  https://orcid.org/0000-0002-1261-8575
Song, Chao 
Schiattarella, Chiara 
Salih, Mohammed 

Abstract

Harmonic generation is a result of a strong non-linear interaction between light and matter. It is a key technology for optics, as it allows the conversion of optical signals to higher frequencies. Owing to its intrinsically large and electrically tunable non-linear optical response, graphene has been used for high harmonic generation but, until now, only at frequencies < 2 THz, and with high-power ultrafast table-top lasers or accelerator-based structures. Here, we demonstrate third harmonic generation at 9.63 THz by optically pumping single-layer graphene, coupled to a circular split ring resonator (CSRR) array, with a 3.21 THz frequency quantum cascade laser (QCL). Combined with the high graphene nonlinearity, the mode confinement provided by the optically-pumped CSRR enhances the pump power density as well as that at the third harmonic, permitting harmonic generation. This approach enables potential access to a frequency range (6-12 THz) where compact sources remain difficult to obtain, owing to the Reststrahlenband of typical III-V semiconductors.

Description

Acknowledgements: We thank Oleg Mitrofanov for helpful discussions. We acknowledged funding from the European Union through the FET Open project EXTREME IR (944735), the Graphene Flagship, and EPSRC programme grants HyperTerahertz (EP/P021859/1) and TeraCom (EP/W028921/1), EPSRC Grants EP/K01711X/1, EP/K017144/1, EP/N010345/1, EP/L016087/1, EP/X015742/1, EP/V000055/1, EP/X015742/1, ERC grants Hetero2D, GSYNCOR, GIPT, EU grants CHARM, Graph-X.

Keywords

40 Engineering, 4009 Electronics, Sensors and Digital Hardware, 51 Physical Sciences, 5104 Condensed Matter Physics

Journal Title

Nat Commun

Conference Name

Journal ISSN

2041-1723
2041-1723

Volume Title

15

Publisher

Springer Science and Business Media LLC
Sponsorship
Engineering and Physical Sciences Research Council (EP/K01711X/1)
Engineering and Physical Sciences Research Council (EP/K017144/1)
Engineering and Physical Sciences Research Council (EP/L016087/1)
Engineering and Physical Sciences Research Council (EP/P021859/1)
Engineering and Physical Sciences Research Council (EP/W028921/1)
EPSRC (EP/X015742/1)