Fig. 1. Classification of OAM multiplexing holography

Fig. 2. OAM holography. (a) Spatial-frequency analysis of helical phase plates in the image plane^[73]; (b) design principle of an OAM-conserving meta-hologram^[75]; (c) design principle of an OAM-selective meta-hologram^[75]; (d) design principle of an OAM-multiplexing meta-hologram^[75]; (e) experimental reconstruction of four distinctive OAM-dependent holographic images^[75]

Fig. 3. Polarization-encrypted OAM- multiplexed metasurface holography. (a) Hologram with plane wave and vortex beam illumination^[77]; (b) schemes of OAM-encrypted holography^[78]; (c) numerical and experimental reconstructions of eight distinctive OAM holographic images through incident circularly polarized vortex beams^[79]; (d) schematic of the OAM meta-transformer designed based on three OAM states^[80]; (e) reconstruction of color images^[80]

Fig. 4. OAM nonlinear hologram. (a) Multichannel nonlinear holographic display based on the OAM multiplexing nonlinear holography^[84]; (b) concept of wavelength-multiplexing nonlinear holography^[85]; (c) concept of multichannel nonlinear holography^[85]

Fig. 5. Metasurface dynamic holography. (a) SEM image of the metasurface sample and schematic illustration of switchable radially polarized beams upon H₂ and O₂ loading^[89]; (b) simulated and experimental results upon H₂ and O₂ loading^[89]; (c) schematic of ultrahigh-dimensional OAM-multiplexed holography based on a large-scale complex-amplitude OAM-multiplexed metasurface hologram^[90]; (d) comparisons of depth multiplexing OAM holography with and without random phases^[91]

Fig. 6. Jump gradient factors-based and angular multiplexation of partial helical phase modes in OAM multiplexing holography. (a) The intensity patterns of the remainder-phase optical vortex^[93]; (b) design principle of modulated OAM-selective holography^[93]; (c) three reconstructed images resulting from an incident modulated beam^[93]; (d) principle of partial OAM holography^[94]; (e) design procedure of a partial OAM hologram^[94]; (f) reconstruction results of partial OAM holograms with φ₀=π/2 and φ₀=π^[94]

Fig. 7. Ellipticity-encrypted OAM multiplexed holography and radial-angular OAM multiplexed holography^[97]. (a) Elliptic optical vortices with different ellipticities; (b) illustration of ellipticity-encrypted OAM multiplexing holography; (c) ultra-fine OAM multiplexing holography; (d) two-dimension spatial division multiplexed holography

Fig. 8. Optical multiplexing and demultiplexing of 16 QR codes in the same spatial region^[99]