A multifunction tunable terahertz chiral metasurface based on graphene and photosensitive silicon

We proposed a chiral metasurface which can realize absorption, circular dichroism (CD) and line-to-circular polarization conversion (LTC-PC). Additionally, by varying the Fermi energy level (Ef) of graphene, the amplitude of the absorption can be changed for specific application. CD can also be dynamically tuned by adjusting the conductivity of photosensitive silicon (PS). Furthermore, by rotating the meta-atom of the chiral metasurface, Panchalatnam-Berry (PB) phase can be obtained. By designing different reflection phase distributions, dynamically tunable anomalous reflections, vortex beams, and focusing can be realized. This design offers new methodologies for optical modulators, communications, image processing, and other related fields.