Breaking the Trade‐off: Single‐Element Metagratings for Multibeam Wavefront Engineering

ABSTRACT Metagratings have emerged as a powerful platform for efficient electromagnetic wave control. Fundamentally, a trade‐off exists between architectural complexity and functional diversity: a single meta‐atom per period can only suppress one diffraction order, typically enabling anomalous reflection and dual‐beam splitting in the case of two and three propagating orders, respectively. Achieving control over more diffraction modes necessitates introducing additional meta‐atoms within the period, increasing design and fabrication challenges. Here, we challenge this prevailing paradigm and demonstrate that a single meta‐atom‐based period is sufficient for advanced wavefront manipulation, far beyond established limitations. We develop a theoretical framework showing that, even in a configuration with two propagating orders, a single meta‐atom per period not only allows achieving high‐efficiency anomalous reflection but also exceptional beam splitting. In scenarios with three propagating orders, both dual‐ and tri‐beam splitting can be achieved. Furthermore, the efficient control of multiple beams with up to five diffraction modes can be successfully accomplished. Our findings overturn the conventional design rule for metagratings, demonstrating that structural complexity is not a prerequisite for advanced functionality. This work paves the way for a new generation of high‐performance and facile‐to‐fabricate wavefront‐control devices with promising applications in wireless communications and imaging systems.