Fabrication of Ge₂Sb₂Te₅ metasurfaces by direct laser writing technique

We experimentally demonstrate fabrication of the tunable high-contrast periodic metasurfaces from 150 nm thick Ge₂Sb₂Te₅ films sputtered onto glass and sapphire substrates by exploiting direct laser writing technique. We find that the use of sapphire substrate provides better accuracy of metasurface segments due to higher thermal conductivity. The advantages of the demonstrated method are its simplicity, rapidity, robustness, and the ability of tailoring dielectric properties of the fabricated structures. This is of crucial importance for the engineering of robust and tunable metasurfaces for applications in the field of telecommunications and information processing.