Near‐Infrared Polarimetric Imaging With Nonlinear Flat‐Optics

ABSTRACT A compact and broadband polarimetric imaging platform is presented, based on second‐harmonic generation (SHG) in nonlinear flat‐optics. The system employs periodic all‐dielectric AlGaAs gratings to induce polarization‐dependent SH emission, enabling pixel by pixel direct retrieval of the full Stokes vector from an input intensity distribution in the near‐infrared range. By engineering the geometry and orientation of the polarimetric units, sensitivity to linear and circular polarization components is achieved. A superpixel design comprising four polarimetric structures allows accurate reconstruction of the polarization state without moving parts or sequential measurements. This approach offers a scalable, passive, and cost‐effective solution for polarimetric imaging, particularly suited for near‐infrared applications.