Linear optical switch metasurface composed of cross-shaped nano-block and [formula omitted] film

Abstract

The all-dielectric metasurface composed of nanostructured materials with a large dielectric constant is the latest research trend of metasurfaces, which overcomes the ohmic loss of metal metasurfaces at optical frequencies. However, once the metasurface is manufactured, its function is usually fixed, which has certain limitations for system integration and practical applications. Therefore, the all-dielectric metasurfaces that can be dynamically reconfigured and controlled have attracted more attention. Here, we present a design based on an optical switch metasurface consisting of a Ge2Sb2Te5 (GST-225) film with phase transition properties. Changing the crystalline state of GST-225, the maximum transmittance difference of meta-atoms is 0.7. Then, we demonstrate the deflective optical switch based on the dynamic control of the metasurface. By numerical simulation results, the proposed metasurface can modulate 1550 nm linearly polarized light, the average transmission efficiency difference can be up to 50.4%. Besides, a two-dimensional meta-lens based on the designed meta-atoms with sensitive switching performance is presented. We believe that the design and application in this work are significant for the design of reconfigurable and efficient metasurface light modulators.