Wavelength- and angle-multiplexed full-color 3D metasurface hologram.

Metasurface holography is a promising technology for next-generation 3D displays, however, conventional approaches for full-colorization have faced challenges. Wavelength multiplexing based on spatial segmentation/interleaving inevitably reduces pixel density, while techniques reliant on the Pancharatnam-Berry (PB) phase are inherently polarization-dependent and have a theoretical efficiency limit of 50 %. In this work, we propose and experimentally demonstrate a design strategy that overcomes these limitations. The core of our approach is a single, polarization-independent meta-atom, realized with cross-shaped nanopillars made of silicon nitride (SiN), which enables the simultaneous and independent phase control over the three primary colors required for faithful 3D image reconstruction. This single-unit strategy surpasses the pixel density limitations of wavelength multiplexing. Furthermore, we combine this innovation with crosstalk elimination via spatial division of target 3D images and precise angle correction to ensure high-fidelity, superimposed reconstruction. Experimentally, we have successfully reconstructed high-definition, noise-free 3D full-color holograms. Our work resolves the critical limitations of pixel density and polarization dependence in metasurface holography, providing a robust pathway toward practical, high-performance holographic displays.