Epitaxial VO2 nanostructures: A route to large-scale, switchable dielectric metasurfaces

Epitaxial VO2 nanostructures: A route to large-scale, switchable dielectric metasurfaces

Článek WoS

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 nano-lithographic fabrication, we prepared a large-area (>1 cm2), deep-subwavelength (thickness of ~ /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.

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 nano-lithographic fabrication, we prepared a large-area (>1 cm2), deep-subwavelength (thickness of ~ /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.

vanadium dioxide; plasmonics; phase transition; near-infrared modulation; metasurfaces; metamaterials

vanadium dioxide; plasmonics; phase transition; near-infrared modulation; metasurfaces; metamaterials

LIGMAJER, F.; KEJÍK, L.; TIWARI, U.; QIU, M.; NAG, J.; KONEČNÝ, M.; ŠIKOLA, T.; JIN, W.; HAGLUND, R.; APPAVOO, K.; LEI, D.

2019

07.05.2018

2330-4022

ACS Photonics

5

7

Spojené státy americké

2561

2567

7

https://pubs.acs.org/doi/10.1021/acsphotonics.7b01384

_FINAL-published
Ligmajer ACSP - VO2 preprint