EIT-like all-dielectric metamaterials with phase changing layers for all-optical switching applications
Publication date: 1 Gen 2017
In this work, we propose the hybridization of all-dielectric metasurfaces based on Si nanoresonators with thin layers of phase change materials (PCM). The concept of all-dielectric metasurfaces is important when one needs to avoid inherent ohmic losses in metal-based nanostructures, e.g. for high Qfactor and figure of merit (FOM). Si nanoresonators can possess electric and magnetic resonances while having low losses in the desired range. On the other hand, chalcogenide PCM have at least two phases with different optical properties, stable at room temperature; switching between these two phases can be reversibly done by a visible laser. If a thin PCM layer is put in contact with Si nanoresonator, its phase-change will change the dielectric environment of the nanoresonator, thus changing the overall resonant response. We numerically investigate the all-optical switching in telecom range of the metasurface based on nanorods and square-like nanorings, namely “bright” and “dark” nanoresonators, respectively. We then experimentally report on the PCM switching metasurface based on nanorods, i.e. “bright” resonators. We strongly believe that this research could lead to new perspectives in all-optical, all-dielectric nanophotonics.