Magnetic modulation of light using a Gires-Tournois Nanocavity and metasurface
Year: 2026
Authors: Santonocito A., Patrizi B., Gabbani A., Agio M., Flatae AM., Bolivar PH., Kienitz P., Toci G., Pineider F.
Autors Affiliation: CNR, Ist Nazl Ott, Via Madonna Piano 10, I-50019 Sesto Fiorentino, FI, Italy; Univ Siegen, Lab Nano Opt, Walter-Flex-Str 3, D-57072 Siegen, Germany; Univ Siegen, Inst High Frequency & Quantum Elect, Holderlinstrasse 3, D-57076 Siegen, Germany; Univ Siegen, Inst Graphene Based Nanotechnol, Holderlinstrasse 3, D-57076 Siegen, Germany; Univ Pisa, Dipartimento Chim & Chim Industriale, Via Moruzzi 13, I-56124 Pisa, Italy.
Abstract: We experimentally demonstrate the enhancement of magneto-optical properties in the visible and near infrared spectral regime by employing Gires-Tournois (GT) resonant architectures based on cobalt. Two distinct systems are investigated: a planar GT cavity composed of a thin Co layer, a silica spacer, and another thin cobalt layer coating a thick aluminium substrate; and a GT metasurface with the same multilayer architecture, but where the top continuous cobalt layer is replaced by a periodic array of cobalt disk-shaped meta-atoms. Through a careful sample realization and characterization, we experimentally demonstrate that both structures achieve an order of magnitude increase in the polar Magneto-Optical Kerr Effect (p-MOKE) to 200 nm cobalt film. This result is analyzed by means of a combination of analytical models and numerical simulations. This enhancement is mainly attributed to constructive interference within the GT cavity and to the synergistic effects of localized surface plasmon resonances, surface lattice resonances and optical cavity modes in the metasurface. These results establish a promising platform for the development of compact, magneto-optically tunable nanophotonic devices with potential applications in nonreciprocal photonics, active optical modulation, and sensing technologies.
Journal/Review: OPTICS AND LASER TECHNOLOGY
Volume: 204 Pages from: 116333-1 to: 116333-14
More Information: This activity has been supported by:the German Research Foundation (DFG) for usage of major equipment under project number INST22 1/169-1FUGG and INST221/170-1FUGG. Part of this work was performed at the Micro-and Nanoanalytics Facility (MNaF) of the University of Siegen.the Regione Toscana grant under the program Progetti di Alta Formazione attraverso l’attivazione di assegni di ricerca, European Union, European Social Fund 2021-2027. Link: https:// www.regi one.toscana.it/-/transizione-verde-finanziamenti-per-progetti-di-alt a-formazione-con-assegni-di-ricerca.The European Union under the European Innovation Council grant agreement N. 101161583, project GreenSWap, link https://greenswapspace.eu/.KeyWords: Tunable Metasurfaces; Gires-Tournoisinterferometers; Fabry-Perot Intensity Modulator; Ferromagnetic Cobalt Nanostructures; Magneto-optical Metasurfaces; MagnetoplasmonicsDOI: 10.1016/j.optlastec.2026.116333
