Tunable Terahertz metamaterials based on hybrid integration of the VO2 metal-insulator transition material

Jonathan Leroy (1) , Georges Humbert (2) , Jean-Christophe Orlianges (3) , Corinne Champeaux (3) , Pierre Blondy (1) , Aurelian Crunteanu (1)

1 XLIM-MINACOM - MINACOM
2 XLIM-PHOTONIQUE - PHOTONIQUE
3 Axe 2 : procédés de traitements de surface

Despite a high application potential, the use of terahertz (THz) frequencies for communication technologies is currently limited by the small number of existing terahertz components and, in particularly, of tunable THz devices. Our approach for obtaining tunable functions in the THz frequency region is to combine a THz “passive” metamaterial (twodimensional array of periodical sub-wavelength metallic structures fabricated on a sapphire substrate) and a vanadium dioxide (VO2) thin film (or structured VO2 patterns) deposited on the same substrate. The interest in using VO2 in the design of metamaterials comes from its ability to perform a reversible phase transition (or metal-insulator transition - MIT) from a semiconductor state (at room temperature) to a metal state (at temperatures higher than 68°C). The MIT is accompanied by large, abrupt changes in the material’s electrical and optical properties (resistivity, refractive index, and permittivity) for frequencies from RF-microwave up to the THz and optical regions. In VO2 thin films the MIT can be triggered using different external stimuli: temperature, electronically or optically and even under external stress or pressure. The transition time can occur on timescales as low as hundreds of femtoseconds for the optically-activated transition, while for the electrically-triggered MIT, activation times down to few nanoseconds have been reported. We will present the design, simulation, fabrication and practical demonstration of tunable VO2-based THz metamaterials devices. We show that the broadband metal-insulator transition (MIT) of VO2 leads to significant variations in the THz transmission of the realized structures (as recorded by terahertz time-domain spectroscopy (THz- TDS) in the frequency range 0.1-1 THz) under the effect of thermal stimuli but also by applying an electric voltage across the metametarial device.

Domaines: Micro et nanotechnologies/Microélectronique; Electromagnétisme; Matériaux

Jonathan Leroy, Georges Humbert, Jean-Christophe Orlianges, Corinne Champeaux, Pierre Blondy, et al.. Tunable Terahertz metamaterials based on hybrid integration of the VO2 metal-insulator transition material. THE 8th INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS, ROCAM 2015, Jul 2015, Bucarest, Romania. ⟨hal-01223118⟩