Progress in metasurfaces based on Ge–Sb–Te phase-change materials

Recently, metasurfaces based on phase-change materials (PCMs) have attracted increasing attention due to the dramatic optical properties contrast between amorphous and crystalline states. The chalcogenide PCMs can be reversibly switched by electrical or optical pulses, offering tunability and reconfigurability for the metasurfaces. In this Perspective, the latest achievements and ongoing development in reconfigurable metasurfaces based on chalcogenide PCMs are presented, including the applications in nonlinear optics, anapole control, beam steering, perfect absorbers, and polaritons. This Perspective ends with perspectives for the growing demands of PCMs based on metasurfaces.