Full stokes parameters detection through high-Q nonlocal metasurfaces composed of simple and identical elliptical nanoposts

We present nonlocal chiral metasurfaces with a relatively high-Q factor for the direct detection of Stokes parameters. To realize it, we leverage the optimized interaction between nonlocal and local resonances in a constituent nanostructured meta-unit. By revealing the working principles of such interaction, we experimentally demonstrate effective nonlocal resonance-based high-Q polarimetric detection, which affords the direct tracking of azimuthal and ellipticity paths at the Poincaré sphere. Such metasurfaces are demonstrated by designing nanostructured meta-units with minimal geometric perturbation from the circular nanopost and keeping the filling ratio of meta-units to be constant for all targeted Stokes metasurfaces. We further prove that such design approach ensures consistent sized nanofabrication and facilitates effective operation across different samples at specific wavelengths and polarizations in experimental setups.