Fig. 5
From: Recent advances in multi-dimensional metasurfaces holographic technologies
OAM-multiplexed metasurface holography. a Schematic illustrations of OAM-conserving, −selective, and -multiplexing meta-holograms. The OAM-multiplexing meta-hologram can reconstruct multiple distinctive holographic images by using different OAM modes [83]. b A 10 bit OAM-multiplexing hologram for high-security holographic encryption. Ten high order OAM modes can be used to reconstruct ten OAM-dependent digits [84]. c An OAM meta-transformer which can reconstruct “0”, “3” and “6” by designed three OAM states, respectively [85]. d The principle of vortex and polarization encryption based on proposed metasurfaces. Different holographic images can be reconstructed by either Gaussian beams (l = 0) or vortex beams carrying a specific OAM (l = 20 or 40) at different polarization channels [86]