Perovskite-oxide based hyperbolic metamaterials
We have shown that conducting LaxSr1-xTiO3 (LSTO) presents excellent plasmonic properties in the near- to mid-infrared region, and that these properties can be tuned with unrivalled flexibility by controlling the La composition. Taking advantage of this outstanding plasmonic response, we have demonstrated a new class of hyperbolic metamaterials (HMMs) composed of LSTO/SrTiO3 (STO) epitaxial superlattices showing a high figure of merit in a spectral range not currently available with other known HMMs. The epitaxial nature of these HMMs combined with the tunability of the LSTO plasmonic response provides ultimate control on their dielectric properties, including their hyperbolic wavelength range. The epitaxial coherency and atomic level abruptness of the LSTO/STO interfaces supporting the plasmon resonances contribute to their low absorption losses. These HMMs involve individual layers with very low thicknesses (few nanometers), and can be combined by epitaxy to the many members of the functional oxide family, opening perspectives for their very compact integration in multifunctional heterostructures. They can also be epitaxially grown on Si and GaAs technological platforms by epitaxy using SrTiO3/Si and SrTiO3/GaAs templates, making them perfectly suited for versatile integration in nanophotonic devices.
Référence : Mohamed Bouras, Dong Han, Sébastien Cueff, Romain Bachelet and Guillaume Saint-Girons, “Perovskite-oxide based hyperbolic metamaterials”, ACS Photonics, just accepted manuscript.
DOI : https://doi.org/10.1021/acsphotonics.9b00485
Twitter : https://twitter.com/ACSPhotonics/status/1143562168383791104