Anisotropic Metagratings for Simultaneous Polarization Conversion and Anomalous Reflection

We present a semi-analytical framework for designing highly efficient polarization and wavefront manipulating metagratings (MGs). The required anisotropy is achieved by introducing rotated dipole scatterer lines as meta-atoms in these sparse periodic composites, using an extended analytical model to capture the polarized near- and far-field interactions between the elements. By tying the MG degrees of freedom, namely, the meta-atom rotation angle, position, and induced current, to the scattered fields, this model enables resolution of the MG configuration that would realize a given (desirable) combined polarization conversion and anomalous reflection. This approach, verified in commercial solvers, presents an appealing alternative for tensor metasurfaces typically utilized to realize such functionalities, featuring simpler meta-atoms, sparser designs, and minimal reliance on full-wave optimizations. These results further augment the range of MG-based solutions, marking an important milestone towards achieving a complete control of scattered fields via this platform.