Stokes Parameter Maps for Figure 4 – Poincaré Beams from a Free Electron Laser

This dataset contains spatially resolved, normalized Stokes parameter maps (s1s_1s1​, s2s_2s2​, and s3s_3s3​) used to generate the polarization plots in Figure 4 of the publication:<br>"Poincaré Beams from a Free Electron Laser", submitted to <i>Nature Photonics</i> (2025).The data are provided in HDF5 format and represent fully processed values after background subtraction, alignment, and normalization. These arrays were used to compute the polarization ellipse distributions, the Poincaré sphere coverage, and the histograms shown in Figure 4.