Wideband polarization-insensitive dielectric switch for mid-infrared waves realized by phase change material Ge3Sb2Te6

We report a dielectric switch consisting of a periodic array of Ge3Sb2Te6 cubes on a silica substrate. When the Ge3Sb2Te6 switches from the crystalline state to the amorphous state, the designed metasurface shows the ability to change from the reflecting state to the transmitting state at mid-infrared frequencies. A reflection coefficient of 96% is realized by simultaneously exciting magnetic and electric dipole modes in the crystalline state while reflection is very small in the amorphous state. Great characteristics of polarization insensitivity and tolerance to large incident angle are also obtained. Copyright (C) EPLA, 2019