Chalcogenide hyperbolic metamaterial with switchable negative refraction

Chalcogenide glasses are exceptional materials that show a wide contrast in optical properties upon phase change and are highly researched for reconfigurable electronic and nanophotonic devices. Here, we report the first proof-of-concept demonstration of a non-volatile, switchable hyperbolic metamaterial based on a chalcogenide glass. By using the $G{e}_{2}S{b}_{2}T{e}_5$ (GST) alloy as one of the components of a multilayered nanocomposite structure and exploiting its phase change property, we demonstrate a hyperbolic metamaterial in which the Type-I hyperbolic dispersion $({\epsilon}{\perp} < 0, {\epsilon}{\parallel} > 0)$ can be switched from the near infrared to the visible region. This opens up new opportunities for reconfigurable device applications, such as imaging, optical data storage and sensing.