Switchable multifunctional metasurface based on electromagnetically induced transparency and photosensitive silicon

In this paper, a multifunctional metasurface are studied based on Electromagnetically Induced Transparency (EIT) and photosensitive silicon. The study explores various functionalities such as refractive index sensing, slow light, optical switch, and optical energy flux sensing measurement. When the photosensitive silicon is not excited, the response of the metasurface is EIT, creating a transparent window, thereby achieving refractive index sensing and slow light effect. Upon excitation of the photosensitive silicon, it functions as a light-controlled switch. The conductivity of the photosensitive silicon determines the transmittance of the front valley, indicating the state of the switch (closed or open). Furthermore, by correlating different electrical conductivity values with the corresponding transmittance, the device enables the measurement of light flux. This design has potential applications in slow light devices, as well as in fields such as biomolecular recognition, environmental monitoring, and optical energy calculation.