Fig. 1. Metalens polarization detecting system. (a) Setup of metalens polarization system; (b) polarization detection principle; (c) scanning electron microscope (SEM) pictures of metalens units

Fig. 2. Reference state of regular polyhedron corresponds to equivalent weighted variance

Fig. 3. Mean error of 18 polarization states after being calibrated with four calibration reference states under different signal-to-noise ratios (inset: schematic diagram of the positions of 18 polarization states on the Poincaré sphere)

Fig. 4. Experimental setup for calibration