Reversible switching of electromagnetically induced transparency in phase change metasurfaces

Metasurface analogue of the phenomenon of electromagnetically induced transparency (EIT) that is originally observed in atomic gases offers diverse applications for new photonic components such as nonlinear optical units, slow-light devices, and biosensors. The development of functional integrated photonic devices requires an active control of EIT in metasurfaces. We demonstrate a reversible switching of the metasurface-induced transparency in the near-infrared region by incorporating a nonvolatile phase change material, Ge2Sb2Te5, into the metasurface design. This leads to an ultrafast reconfigurable transparency window under an excitation of a nanosecond pulsed laser. The measurement agrees well with both theoretical calculation and finite- difference time-domain numerical simulation. Our work paves the way for dynamic metasurface devices such as reconfigurable slow light and biosensing.