Electromagnetic Duality Metagratings for Transparency with Minimized Specular Reflection

Recently, transparent metasurfaces with tailored diffusive reflection have attracted great attention due to their transformative potential in future glare-free optical designs. In this work, we propose a class of electromagnetic duality metagratings composed of a pair of dual meta-atoms, which are generated from the combined operations of duality transformation and 90° rotation. We rigorously prove that such gratings guarantee distortion-free transmission with minimized specular reflection, regardless of the details of the meta-atoms. Such a remarkable property, protected by the dual relation between the meta-atoms, has been validated through full-wave simulations and microwave experiments (9.1–9.5 GHz). Our work unveils the fundamental role of electromagnetic duality symmetry in meta-device designs, opening new avenues toward transparency with minimized specular reflection and offering promising applications in antireflection and stealth technologies.