Multiplexing Vectorial Holographic Images with Arbitrary Metaholograms

Metasurfaces achieving arbitrary phase profiles within ultrathin thickness, emerge as miniaturized, ultracompact, and kaleidoscopic nanophotonic platforms. However, it is often required to segment or interleave independent subarray metasurfaces to multiplex holograms in a single nanodevice, which in turn affects the device's compactness and channel capacity. Here, a flexible strategy is proposed for multiplexing vectorial holographic images by controlling the phase distributions of holographic images in far field. Benefitting from precisely controlling the phase difference of reconstructed images through the modified Gerchberg-Saxton algorithm, two different holographic images are independently designed for the circular light by two interleaved metasurfaces and an extra vectorial hologram is flexibly encrypted in far field without additional set of structures on the metasurface plane. An unlimited number of polarization can be achieved in the holographic image and additional information can be decrypted when different polarization-dependent holographic images overlap. By continually varying phase difference between the incident right and left circular polarized light, the image within the overlap area can be modulated. The silicon dielectric metahologram with record absolute multiplexed efficiency (>25%) is achieved in the experiment. This technique, as far as it is known, promises an enormous data capacity as well as a high level of information security.

Automated summary

This study proposes a flexible strategy for multiplexing vectorial holographic images by controlling phase distributions in the far field. By independently designing different holographic images and flexibly encrypting another vectorial hologram in the far field, higher efficiency and data security can be achieved in a single nanodevice.