具有可切换手性光学响应的全介质双原子超表面

Chirality, which generally manifests itself as the inability to coincide with its mirror image structure by translation or rotation. In optics, the interaction between chiral structures and circularly polarized light produces circular dichroism (CD), which has great applications in polarization switching, filtering, and sensing. Here, a design strategy is proposed for a singlcwlayer all-dielectric diatomic metasurface working in the near-infrared (NIR) band, where the interference effect generated between neighboring nanoscale silicon pillars is capable of inducing spin-selective transmission of circularly polarized light, producing up to 95. 33% of the CD amplitude at 292. 33 THz. The metaface unit can be reconfigured by varying the relative rotation angle of the right cross elliptical silicon pillars, further providing a flexible way to switch the type of response for CD spectrum. The proposed design can also be employed as a polarization converter from linearly to circularly polarized light and still have reconfigurable properties. Therefore o the designed diatomic chiral metasurfaces can be generally applied to dynamic multifunctional devices, which provides a new idea for the design and development of integrated photonic devices.