High‐Dimensional Solar‐Blind Ultraviolet Communication Enabled by Diamond Metasurfaces

Free‐space optical (FSO) communication is a promising technology for high‐speed data transmission, offering high bandwidth, license‐free spectrum, and immunity to electromagnetic interference. Solar‐blind ultraviolet (UV) communication provides a compelling alternative to conventional visible/infrared FSO by enabling non‐line‐of‐sight links, which are essential for complex environments. This spectral band also features enhanced security and low interference, owing to minimal solar background radiation and strong atmospheric scattering. However, the practical deployment of solar‐blind FSO systems is hindered by the bulkiness and weight of conventional refractive optical components. Here, we report a compact and multifunctional solar‐blind communication platform that combines wide bandgap semiconductor‐based photodetectors with the diamond metasurface technology. By exploiting the ability of diamond metasurfaces to simultaneously manipulate the phase and polarization properties of solar‐blind UV light, we demonstrate an optical communication system that utilizes high‐dimensional states of light. The system achieves enhanced effective photoresponsivity and supports polarization‐selective and polarization‐multiplexed communication protocols. This work establishes a pathway toward miniaturized, lightweight, and versatile solar‐blind FSO systems capable of operation in demanding scenarios, highlighting their significant potential for real‐world applications.