Fidelity-enhanced filter-free OAM holography via polarization-assisted metasurfaces

Orbital-angular-momentum (OAM) beams provide high-dimensional channels for metasurface holography, but their ideal orthogonality is strongly degraded in finite, discretized metasurfaces. In filter-free OAM multiplexing, multiple holographic channels therefore compete for limited structural modulation degrees of freedom, leading to severe crosstalk and reduced reconstruction fidelity. Here, we propose polarization-assisted vortex holography, in which an orthogonally polarized component is introduced as an auxiliary coherent degree of freedom rather than an independent decoding channel. By jointly exploiting the OAM-dependent helical phase and the polarization-dependent Jones response of the metasurface, the method redistributes the encoding burden among vectorial field components and relaxes the OAM-only modulation constraint. Full-wave simulations show that the proposed strategy consistently improves image correlation and channel distinguishability compared with conventional OAM-only multiplexing under identical filter-free conditions. We further demonstrate its compatibility with output-polarization and propagation-distance multiplexing, enabling 10 filter-free holographic channels. This work establishes polarization assistance as a compact vectorial mechanism for high-fidelity OAM metasurface holography.