Achieving 100% amplitude modulation depth in the terahertz range with graphene-based tuneable capacitance metamaterials

Ruqiao Xia; Nikita W. Almond; Wadood Tadbier; Stephen J. Kindness; Riccardo Degl'Innocenti; Yuezhen Lu; Abbie Lowe; Ben Ramsay; Lukas A. Jakob; James Dann; Stephan Hofmann; Harvey E. Beere; Sergey A. Mikhailov; David A. Ritchie; Wladislaw Michailow

doi:10.1038/s41377-025-01945-4

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Achieving 100% amplitude modulation depth in the terahertz range with graphene-based tuneable capacitance metamaterials

Original Articles

- Achieving 100% amplitude modulation depth in the terahertz range with graphene-based tuneable capacitance metamaterials
- Light: Science & Applications Vol. 14, Issue 9, Pages: 2736-2751(2025)
- Affiliations：
  
  1.Cavendish Laboratory, University of Cambridge, Cambridge, UK
  2.Department of Engineering, University of Cambridge, Cambridge, UK
  3.School of Electronic Engineering and Computer Science, Queen Mary University of London, London, UK
  4.Department of Electronic & Electrical Engineering, Faculty of Engineering Sciences, University College London, London, UK
  5.Institute of Physics, University of Augsburg, Augsburg, Germany
  6.Centre for Integrative Semiconductor Materials and Department of Physics, Swansea University, Swansea, UK
- Author bio：
  
  Ruqiao Xia (rx224@cam.ac.uk)
  Wladislaw Michailow (wm297@cam.ac.uk)
- Funds：
- DOI：10.1038/s41377-025-01945-4
  CLC：
- Received：17 December 2024，
  
  Revised：2025-05-27，
  
  Accepted：30 June 2025，
  
  Published Online：04 August 2025，
  
  Published：30 September 2025
- Accepted：
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Xia, R X. et al. Achieving 100% amplitude modulation depth in the terahertz range with graphene-based tuneable capacitance metamaterials. Light: Science & Applications, 14, 2736-2751 (2025).
DOI：

Xia, R X. et al. Achieving 100% amplitude modulation depth in the terahertz range with graphene-based tuneable capacitance metamaterials. Light: Science & Applications, 14, 2736-2751 (2025). DOI： 10.1038/s41377-025-01945-4.

摘要

Abstract

Effective control of terahertz radiation requires fast and efficient modulators with a large modulation depth—a challenge that is often tackled by using metamaterials. Metamaterial-based active modulators can be created by placing graphene as a tuneable element shunting regions of high electric field confinement in metamaterials. However

in this common approach

the graphene is used as a variable resistor

and the modulation is achieved by resistive damping of the resonance. In combination with the finite conductivity of graphene due to its gapless nature

achieving 100% modulation depth using this approach remains challenging. Here

we embed nanoscale graphene capacitors within the gaps of the metamaterial resonators

and thus switch from a resistive damping to a capacitive tuning of the resonance. We further expand the optical modulation range by device excitation from its substrate side. As a result

we demonstrate terahertz modulators with over four orders of magnitude modulation depth (45.7 dB at 1.68 THz and 40.1 dB at 2.15 THz)

and a reconfiguration speed of 30 MHz. These tuneable capacitance modulators are electrically controlled solid-state devices enabling unity modulation with graphene conductivities below 0.7 mS. The demonstrated approach can be applied to enhance modulation performance of any metamaterial-based modulator with a 2D electron gas. Our results open up new frontiers in the area of terahertz communications

real-time imaging

and wave-optical analogue computing.

关键词

Keywords

references

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