Photo-ionic driven transitions in reconfigurable chalcogenide metasurfaces

Chalcogenide glasses offer a unique platform for the realization of reconfigurable and tunable metasurfaces, as evidenced through the emergence of reconfigurable phase change metamaterials. Reconfiguration in these devices involves a thermally intensive melt/quench phase transition process which can reduce device lifetimes and degrade performance. Notably, metal doped chalcogenide semiconductors also exhibit photo-induced long-range movement of their constituent metal ions in their amorphous phase, resulting in non-volatile changes to refractive index and conductivity, removing the need for a phase transition. We utilize this photo-ionic movement in amorphous nanostructured silver-doped germanium selenide metasurfaces to demonstrate reversible non-volatile switching over optical frequencies.