Epitaxial VO<inf>2</inf> Nanostructures: A Route to Large-Scale, Switchable Dielectric Metasurfaces

Copyright © 2018 American Chemical Society. Metasurfaces offer unparalleled functionalities for controlling the propagation and properties of electromagnetic waves. But to transfer these functions to technological applications, it is critical to render them tunable and to enable fast control by external stimuli. In most cases, this has been realized by utilizing tunable materials combined with a top-down nanostructuring process, which is often complicated and time intensive. Here we present a novel strategy for fabricating a tunable metasurface comprising epitaxially grown nanobeams of a phase transition material, vanadium dioxide. Without the need for extensive nanolithographic fabrication, we prepared a large-area (>1 cm2), deep-subwavelength (thickness of ∼Λ/40) nanostructured thin film that can control light transmission with large modulation depth, exceeding 9 dB across all telecommunication wavelength bands. Furthermore, the transmission in the "on" state remains higher than 80% from near- to mid-infrared region. This renders our metasurface useful also as a phase-shifting element, which we demonstrate by carrying out cross-polarized transmission measurements. To provide insights about the relationship between metasurface morphology and its resulting optical properties, we perform full-field three-dimensional numerical simulations as a function of width, height, and edge-to-edge separation of the epitaxial VO2 nanobeams

Effect of deposition angle on fabrication of plasmonic gold nanocones and nanodiscs

Sem informaçãoMetal nanocones can exhibit several strong plasmonic resonances, which are associated with intense and accessible electromagnetic hot spots. They can thus be used to enhance light-matter interactions or to facilitate location-specific sensing while enabli22816Sem informaçãoSem informaçãoSem informaçãoThis research was carried out under project GA17-33767L of Grant Agency of the Czech Republic, H2020 Twinning programme (project SINNCE, 810626) and Brno University of Technology (project FSI-S-17-4482). The work was also supported by the project CEITEC