Three-Dimensional Array Multicasting of Cylindrical Vector Beams Using Spin-Multiplexed Dammann Vortex Metasurface.

Data multicasting over massive cylindrical vector beam (CVB) channels offers substantial advantages for high-capacity information dissemination in mode-multiplexed communication networks. However, conventional multicasting solutions are confined to one- or two-dimensional operations with limited diversity; multichannel, multimode implementations in three-dimensional (3D) vector space remain largely unexplored, which promises to maximize throughput. Herein, for the first time we develop a volumetric CVB multicasting strategy that introduces 3D multichannel array modes as information carriers. By coherently merging a vectorial Dammann vortex grating and a vectorial Dammann vortex zone plate on a minimalist spin-multiplexed phase-modulation metasurface, array degrees of freedom in both the transverse plane and longitudinal depth are independently regulated, thereby unlocking a 3D multichannel CVB lattice with sufficient mode diversity. As demonstration, we achieve a 3D CVB array generator with an operational dimension of 3 × 3 × 5, and 400 Gbit/s quadrature phase shift keying signals are successfully distributed to up to nine distinct spatial nodes with bit error rates of 10-6. This work provides a compact and scalable platform for volumetric vector-field engineering, opening new pathways for multidimensional optical field manipulation and complex optical node interconnection, which may accelerate advances in optical edge data processing and short-reach communication networking.