Nonvolatile Reconfigurable Electromagnetically Induced Transparency with Terahertz Chalcogenide Metasurfaces

Metasurface analog of electromagnetically induced transparency (EIT) provides a compact platform for generating a narrow-band transmission window with very sharp spectral features. They hold promise for many appealing applications including ultrasensitive detectors, slow-light devices, nonlinear optical devices etc. In particular, reconfigurable EIT metasurfaces are crucial for expanding the capability of light field control, which are promising for terahertz (THz) communications and optical networks. Yet, the investigation on reconfigurable EIT metasurfaces with nonvolatile operation remains scarce. Here, reversible switching of the metasurface-induced transparency in the THz spectrum is experimentally realized. The reconfigurable response (reversible spectral shift) is obtained by integrating a nonvolatile chalcogenide phase change material, Ge2Sb2Te5 (GST225) into the meta-atoms. A giant reversible switching of EIT takes place under an excitation of nanosecond laser pulses, showing a reconfigurable group delay of the THz waves. The proposed reconfigurable THz metadevices may provide a new route for the ultrafast laser induced switching and reconfigurable slow-light devices.