Graphene-based electromechanically tunable subwavelength mid-IR perfect absorber

In this article, we propose and numerically investigate a graphene-based electromechanically tunable perfect absorber design. The fundamental motivation is to demonstrate the electromechanically tunable feature in graphene metasurface at the mid-infrared regime, which otherwise exploited only the ch...

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Bibliographic Details
Published in:Optical and quantum electronics 2023-12, Vol.55 (14), Article 1246
Main Authors: Roy, Shuvajit, Debnath, Kapil
Format: Article
Language:English
Subjects:
Absorbers
Actuation
Beam steering
Characterization and Evaluation of Materials
Chemical potential
Computer Communication Networks
Electric potential
Electrical Engineering
Gold
Graphene
Lasers
Optical Devices
Optics
Photonics
Physics
Physics and Astronomy
Resonance absorption
Substrates
Voltage
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Summary:In this article, we propose and numerically investigate a graphene-based electromechanically tunable perfect absorber design. The fundamental motivation is to demonstrate the electromechanically tunable feature in graphene metasurface at the mid-infrared regime, which otherwise exploited only the chemical potential feature in the literature. The structure consists of a gold grating on a gold substrate separated by an oxide spacer with an overlay of monolayer graphene with free-standing segments. By applying external DC voltages, the free-standing region of the graphene layer deflects, owing to the electrostatic force it experiences. This shifts the resonance absorption wavelength. In the mid-infrared region of 5–10 µm, a very low actuation voltage of 1.6 V displaces the graphene membrane by 1 nm, resulting in a wide shift of 60 nm in resonance wavelength. A continuous tunability with near-perfect absorption over a wavelength range of 200 nm for an applied voltage of only 7 V is demonstrated. At a voltage greater than 7 V, a mode hopping phenomenon is observed, hampering the perfect absorber operations with a shift in wavelengths. It is shown that the perfect absorption is again retained at some higher voltage. Such implementations hold promising applications in nanophotonics sensors, detectors, real-time beam steering, etc.
ISSN:0306-8919
1572-817X
DOI:10.1007/s11082-023-05514-0