Fig. 2. The operational principle of the nanophotonic polarization camera consists of three steps: calibration, capture, and reconstruction.

a Schematic of the calibration process. ➀ denotes a narrowband spectral filter. ➁ denotes an imaging lens. b The responsivity matrix $\mathit{R}$ of the whole meta-device is calibrated from the photoresponses to the three pairs of orthogonal SoPs of incident light. c Schematic of the capture process. Scattered optical waves at each position (x, y) of target scene represented an unknown SoP $\mathit{S}={\left[S_0,S_1,S_2,S_3\right]}^T$, illuminates the imaging system. d A single-shot capture process generates the polarization-encoded image I. e Mathematical description of the relation between ${\mathit{S}}_{\mathit{v}}$, I_v, and $\mathit{\Lambda }$. f SoP reconstruction by the convolutional neural network. g Reconstructed SoP and corresponding position on Poincaré sphere.