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Electrically Tunable Nonlinearity at 3.2 Terahertz in Single-Layer Graphene.

Published version
Peer-reviewed

Repository DOI


Type

Article

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Authors

Di Gaspare, Alessandra 
Zhang, Jincan 
Meersha, Adil 
Shinde, Sachin M 

Abstract

Graphene is a nonlinear material in the terahertz (THz) frequency range, with χ(3) ∼ 10-9 m2/V2 ∼ 15 orders of magnitude higher than that of other materials used in the THz range, such as GaAs or lithium niobate. This nonlinear behavior, combined with ultrafast dynamic for excited carriers, proved to be essential for third harmonic generation in the sub-THz and low (<2.5 THz) THz range, using moderate (60 kV/cm) fields and at room temperature. Here, we show that, for monochromatic high peak power (1.8 W) input THz signals, emitted by a quantum cascade laser, the nonlinearity can be controlled using an ionic liquid gate that tunes the graphene Fermi energy up to >1.2 eV. Pump and probe experiments reveal an intense absorption nonlinearity at 3.2 THz, with a dominant 3rd-order contribution at EF > 0.7 eV, hence opening intriguing perspectives per engineering novel architectures for light generation at frequencies > 9 THz.

Description

Keywords

51 Physical Sciences, 5104 Condensed Matter Physics, 7 Affordable and Clean Energy

Journal Title

ACS Photonics

Conference Name

Journal ISSN

2330-4022
2330-4022

Volume Title

10

Publisher

American Chemical Society (ACS)
Sponsorship
Engineering and Physical Sciences Research Council (EP/L016087/1)
EPSRC (EP/X015742/1)
Engineering and Physical Sciences Research Council (EP/P021859/1)