Switchable supercavity modes in metasurfaces based on phase change materials

The paper considers a switchable high-index metasurface made of Ge₂Sb₂Te₅ compound. Varying the lattice spacing between the scatterers, we examined the fundamental dipole-type mode defining the metamaterial properties. At a certain lattice spacing, the structure has the reliable resonance in spectrum for the case of crystalline phase of Ge₂Sb₂Te₅, while the resonance in the case of amorphous phase degrades completely.