Directional and Polarization‐Encoded Emission Via Rotational Displacement in Nonlocal Metasurfaces

ABSTRACT Realizing nanoscale emitters with simultaneous spectral purity, intrinsic polarization control, and programmable wavefronts remains a pivotal challenge in integrated photonics. Conventional approaches often compromise efficiency by relying on external polarizers or fail to simultaneously optimize resonance quality, field‐emitter overlap, and geometric‐phase tunability. Here, this trade‐off is overcome by manipulating the rotation of eccentric nanodisks with subtle offsets within a diatomic lattice metasurface. The eccentricity‐induced symmetry breaking activates dark electric quadrupole and out‐of‐plane magnetic dipole modes, generating orientation‐tunable net dipoles that govern linear polarization. Crucially, Rayleigh anomaly‐mediated collective coupling preserves high quality factors across a full rotation, ensuring spectral stability. Furthermore, supercell‐based geometric phase gradients are implemented to confirm fully encoded directional and circularly polarized spontaneous emission without chiral materials. Transitioning to high‐index silicon isolates the dual resonances, while tuning the eccentric displacement of the nanodisks induces critical coupling to maximize directional enhancement. Ensemble‐averaged simulations incorporating lattice disorder quantitatively reproduce experimental performance, identifying nanoscale period fluctuations as the primary fabrication constraint. This work establishes a scalable, unified platform for metasurface emitters with independently encoded polarization, beam direction, and spectrum, paving the way for ultracompact metalasers, polarization‐encoded circuits, and efficient quantum light sources.