Miniaturized Full-Stokes Spectrometers Based on Low-Correlation Metasurface Array

Abstract

Full-Stokes spectrometers hold an immense application value due to their capability to simultaneously resolve polarization state and spectral information. Specifically, miniaturized full-Stokes spectrometers are promising for applications in real-world scenarios owing to the significant reduction in optical components and footprint. However, it is considerably challenging to simultaneously possess snapshot capability, small footprint, high spectral resolution, and high spectral accuracy. Herein, we propose a snapshot miniaturized full-Stokes computational spectrometer with an ultracompact footprint of 24.5 μm × 24.5 μm based on silicon nitride (Si₃N₄) metasurfaces possessing low cross-correlation coefficients. Our device achieves narrowband spectral reconstruction in the visible regime with FWHM as narrow as 2.03 nm and a polarization angular distance error of 2.70° on the Poincaré sphere. For broadband spectral reconstruction, the mean absolute error (MAE) of the full-Stokes parameters is 0.056, with a high coefficient of determination (R²) of 0.977 and a cosine similarity of 0.989, alongside a global broadband polarization angular distance error of 4.06°. This work achieves high-fidelity full-Stokes spectral reconstruction within a compact footprint, establishing a robust technological foundation for ultracompact multidimensional light field perception.