Di Gaspare, A, Pogna, EAA, Salemi, L et al. (10 more authors) (2021) Tunable, Grating-Gated, Graphene-On-Polyimide Terahertz Modulators. Advanced Functional Materials, 31 (10). 2008039. ISSN 1616-301X
Abstract
An electrically switchable graphene terahertz (THz) modulator with a tunable-by-design optical bandwidth is presented and it is exploited to compensate the cavity dispersion of a quantum cascade laser (QCL). Electrostatic gating is achieved by a metal grating used as a gate electrode, with an HfO2/AlOx gate dielectric on top. This is patterned on a polyimide layer, which acts as a quarter wave resonance cavity, coupled with an Au reflector underneath. The authors achieve 90% modulation depth of the intensity, combined with a 20 kHz electrical bandwidth in the 1.9–2.7 THz range. The modulator is then integrated with a multimode THz QCL. By adjusting the modulator operational bandwidth, the authors demonstrate that the graphene modulator can partially compensate the QCL cavity dispersion, resulting in an integrated laser behaving as a stable frequency comb over 35% of the operational range, with 98 equidistant optical modes and a spectral coverage 1.2 THz. This paves the way for applications in the terahertz, such as tunable transformation-optics devices, active photonic components, adaptive and quantum optics, and metrological tools for spectroscopy at THz frequencies.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2020 The Authors. Advanced Functional Materials published by Wiley‐VCH GmbH. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made. |
Keywords: | graphene; modulators; polyimide waveguides |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Electronic & Electrical Engineering (Leeds) > Pollard Institute (Leeds) |
Funding Information: | Funder Grant number EPSRC (Engineering and Physical Sciences Research Council) EP/P021859/1 Royal Society WM150029 |
Depositing User: | Symplectic Publications |
Date Deposited: | 03 Jan 2021 17:10 |
Last Modified: | 25 Jun 2023 22:32 |
Status: | Published |
Publisher: | Wiley |
Identification Number: | 10.1002/adfm.202008039 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:169122 |