Broadband Terahertz Transparency in a Switchable Metasurface

Plasmon-induced transparency in terahertz metamaterials markedly modifies the dispersive properties of an otherwise opaque medium and reveals unprecedented prospects on novel functional components. However, plasmon-induced transparency in metamaterials so far exists in a narrow frequency band or without actively tunable abilities. Here, we demonstrate optical control of a broadband plasmon-induced transparency in a hybrid metamaterial made from integrated silicon-metal unit cells. Attributed to the modification in damping rate of the dark mode resonators under optical excitation, a giant dynamic amplitude modulation of the broadband transparency window is observed. The scheme suggested here is promising in developing broadband active slow-light devices and realizing on-to-off switching responses of the terahertz radiation at room temperature.