Multichannel polarization encoded reflective metahologram using VO₂ spacer in visible regime

Optical holography by using metasurfaces has attracted wide attention in three-dimensional imaging techniques. In particular, polarization encoded meta-holography have shown much interest to encode multiple images on a single metasurface. But these metasurfaces either use a separate array of pixels or use additional space on the image plane for encoding and decoding the optical information. Here, we propose a multichannel reflective encrypted metahologram which is aimed to reconstruct distinct holographic images by incident polarizations of light and polarization selectors at the output without any additional meta-atoms or space on the imaging plane. To have full control on our design, we used C-shaped antennas associated with an ultra-thin spacer of phase change material and a back reflector that stores the holographic images on both of output polarizations. This study chooses the extended 3D Gerchberg–Saxton (GS) algorithm to get the desired phase distribution of metasurface hologram. Two distinct holographic images are firstly calculated and then numerically realized by this approach on the same imaging plane. This work suggests a novel route to encrypt optical information, fast data transmission and compact data storage where the limited area is the primary concern.