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Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
Published on: July 24, 2015
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Broadband Tunable THz Absorption with Singular Graphene Metasurfaces.
Emanuele Galiffi1, John B Pendry1, Paloma A Huidobro1
1Department of Physics, The Blackett Laboratory, Imperial College London , London SW7 2AZ, United Kingdom.
ACS Nano
|January 12, 2018
Summary
Researchers developed a broadband, tunable terahertz (THz) absorber using graphene conductivity modulations. This efficient device achieves near-theoretical absorption and enables subwavelength focusing of THz radiation.
Area of Science:
- Terahertz (THz) technology
- Plasmonics
- Materials science
Background:
- Graphene's unique electrical properties offer potential for advanced optical devices.
- Controlling conductivity spatially is key to designing novel photonic structures.
- Terahertz absorbers are crucial for various applications, including sensing and imaging.
Purpose of the Study:
- To design a broadband, tunable terahertz (THz) absorber with high efficiency.
- To investigate the excitation of high-order surface plasmons for subwavelength focusing.
- To explore the potential for high-speed switching applications.
Main Methods:
- Exploiting singular spatial modulations of graphene conductivity.
- Designing an extended structure to support broadband absorption.
- Analyzing field enhancement and surface plasmon excitation.
Main Results:
- Achieved a broadband, tunable THz absorber with efficiency near the theoretical upper bound.
- Demonstrated a fractional bandwidth of 185% for wide absorption.
- Observed strong field enhancement and excitation of high-order surface plasmons.
- Enabled deeply subwavelength focusing of incident THz radiation.
Conclusions:
- The designed graphene-based structure represents a significant advancement in THz absorber technology.
- The ability to excite high-order surface plasmons opens new avenues for THz focusing applications.
- Modulating graphene conductivity at GHz frequencies suggests potential for high-speed broadband switching.
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