Fig. 1. Comparison between conventional spectropolarimetry, metasurface-based spectropolarimetry, and PVB-based spectropolarimetry. (a)–(c) Schematics of DoS method, DoT method, and channeled method. (d) Schematics of metasurface-based spectropolarimetry. (e) Schematics of PVB spectropolarimetry. SOP, state of polarization; BS, beam splitter; R, retarder; D, detector; I, intensity; λ, wavelength; PM, phase modulator; A, analyzer; DOE, diffractive optical element; V, vortex retarder; PVB, polychromatic vector beam.

Fig. 2. Design and fabrication of DOE. (a) Schematic of one SiN_x nanopillar, (b) calculated phase profile and zooming in on central part of it, (c) phase shift of the eight selected SiN_x nanopillars at four representative wavelengths, and (d) SEM results of the fabricated DOE.

Fig. 3. Demonstration configuration of PVB-based spectropolarimeter. The broadband light source, the polarizer (P), and the quarter-wave plate (Q) serve as a broadband polarization state generator. The DOE, achromatic plano-convex lens (L), and vortex retarder (V) convert incident polychromatic waves into collimated PVBs. An analyzer (A) maps the spectrum and polarization into a spatially varying intensity pattern, which is recorded by a scientific CMOS camera for further analysis.

Fig. 4. Fitted relation between the wavelengths and the pixel radii.

Fig. 5. Normalized measured modulated vector a→(r,φ). (a)–(d) represent the parameters a0(φ,r) to a3(φ,r), respectively. The inner and outer pixel radii of the rings are 532 and 940, corresponding to the wavelengths of 399.5 nm and 701.1 nm, respectively.

Fig. 6. Captured RGB intensity images and the obtained intensity variations within VIS range. (a) and (c) Spectrally uniform linearly polarized beam generated by a 30° P. (b) and (d) Spectrally varying polarized beam generated by a 40° P and a 5° Q.

Fig. 7. Measured results and measured error for normalized Stokes vector. (a) and (b) Spectrally uniform linearly polarized beam generated by a 30° P. (c) and (d) Spectrally varying polarized beam generated by a 40° P and a 5° Q.

Fig. 8. Theoretical and experimental data of eight measurements.

Fig. 9. Measured and fitted coefficients during the mutarotation of glucose solution. (a) Evolution of coefficient A. (b) Evolution of coefficient B.

Fig. 10. (a) Measured ORD of α-D-glucose, β-D-glucose, and glucose solution at equilibrium. (b) Concentration variations of α and β anomers during the reaction.