The magnetic response of graphene split-ring metamaterials

• Published in: Light, science & applications Vol. 2; no. 7; p. e78
• Main Authors: Papasimakis, Nikitas, Thongrattanasiri, Sukosin, Zheludev, Nikolay I, García de Abajo, FJ
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.07.2013; Springer Nature B.V
• Subjects: Applied and Technical Physics; Atomic; Classical and Continuum Physics; Confinement; Electric potential; Graphene; Lasers; Magnetic dipoles; Metamaterials; Molecular; Noble metals; Optical and Plasma Physics; Optical Devices; Optics; original-article; Photonics; Physics; Physics and Astronomy; Plasmonics; Wavelengths; artificial magnetism; metamaterials; plasmonics; graphene; graphene plasmons
• ISSN: 2047-7538; 2047-7538
• DOI: 10.1038/lsa.2013.34

Graphene has emerged as a promising platform for THz plasmonics, allowing high confinement, long lifetimes and fast electrical tunability. Here, we predict a strong magnetic dipole response by graphene split nanorings at THz frequencies, allowing the attainment of metamaterials with a high degree of field confinement (approximately one hundredth of the excitation wavelength) that is not reachable with conventional noble metals. The magnetic response of highly doped graphene split-rings in the far-infrared is much stronger than that displayed by gold structures of similar thicknesses. We further explored stacked graphene layers as a practical way of producing high-frequency magnetism in thin, electrically tunable metamaterials. Our results support the great potential of using graphene to achieve electrically tunable magnetic metamaterials. Metamaterials: Graphene split-rings Split-ring metamaterials made from graphene could yield strong magnetic resonance effects in the far-infrared. This is the prediction of Nikitas Papasimakis and co-workers from the University of Southampton, UK, IQFR-CSIC in Madrid, Spain, ICFO in Barcelona Spain, and NTU, Singapore. Their theoretical study into single- and stacked-layer structures suggests that graphene split-rings with diameters of just 1 µm can exhibit large magnetic resonances that peak at around 110 µm in wavelength. Compared with conventional noble metals such as gold and silver, the use of graphene provides a much greater level of field confinement and potential for much smaller ring sizes. Other advantages may include the possibility for ultrathin geometries and the ability to realize an electrically tunable optical response by injecting charge carriers into graphene.