Rochon-Prism-Like Planar Circularly Polarized Beam Splitters Based on Dielectric Metasurfaces

We design and fabricate the Rochon-prism-like planar circularly polarized beam splitters based on dielectric metasurfaces by simultaneously controlling the geometric phase and the propagation phase via manipulation of the orientations and the sizes of the constituent silicon nanoblocks. The special splitters deviate only one of the circular polarizations while leave the other undeviated, acting like a Rochon prism for linearly polarized light, and their efficiencies can be as high as 66.7% with an extinction ratio of 27. The mechanism makes it possible to fabricate metasurface holograms that can only be reconstructed by either of two circular polarizations while hidden from the other. The functionality of beam splitting and polarization dependent decryption based on dielectric metasurfaces enables the potential applications in both miniaturized polarizing optical systems and information security and processing.