High-dimensional multiplexing through vortex electromagnetic wave manipulation by space-time-coding metasurfaces

Orbital angular momentum (OAM) is a fundamental property of light, with widespread applications across various fields, from quantum mechanics to advanced imaging and telecommunications. The inherent orthogonality of OAM beams allows information multiplexing in unique, high-dimensional states. However, conventional OAM-based systems encounter long-standing integration and scalability challenges due to the heavy reliance on complex optical components and redundant radio frequency chains for multi-channel transmission. Here, we propose a dual-polarized asynchronous space-time-coding metasurface (DASM) for producing coaxial OAM beams in multiple physical domains through a single aperture. By synergistically combining OAM, polarization, and frequency division multiplexing, DASM constructs a high-dimensional communication framework, dramatically increasing the number of supported channels. Notably, DASM further streamlines the framework by directly modulating the information carried by OAM beams, eliminating the need for complicated external modulators. The high-dimensional multiplexing framework offers a simplified, versatile, and efficient solution for substantial development in wireless communications capacity and scalability.