Switchable Dielectric Metasurfaces

Metasurfaces offer unparalleled functionalities for controlling the propagation and properties of electromagnetic waves. To transfer these functions to technological applications, it is critical to render them tunable and to enable fast control by external stimuli. However, the recent approaches based on top-down preparation of nanostructures are complicated and time intensive.

Based on a comprehensive analysis of epitaxial VO₂ nanostructures at CEITEC Nano Core facility, F. Ligmajer with his colleagues introduced a new class of tunable plasmonic-dielectric metasurfaces.

The epitaxial growth of VO₂ on a (112̅0) face of sapphire substrate that leads to formation of a thin layer of parallel, closely spaced VO₂ nanobeams. This present a promising metasurface building blocks with deeply subwavelength thickness that can be easily switched from the isotropic transparent dielectric state to the anisotropic opaque metallic state and thus effectively control the flow of light.

F. Ligmajer, L. Kejík, U. Tiwari, M. Qiu, J. Nag, M. Konečný, T. Šikola, W. Jin, R. F. Haglund, K. Appavoo, D. Y. Lei: Epitaxial VO2 Nanostructures: A Route to Large-Scale, Switchable Dielectric Metasurfaces. ACS Photonics 5 (2018), 2561.