Phase-Vortex Removal for Quantitative X-Ray Nanotomography with Near-Field Ptychography

X-ray ptychotomography in the near-field regime is a promising technique for high-resolution, quantitative, and nondestructive investigations in materials science, paleontology, and biomedicine. X-ray near-field ptychography has been previously demonstrated in projection and tomography mode, but the quantitativeness of the reconstructed data has never been discussed in detail. Here, we use measurements of a sample made of aluminum and nickel microparticles to evaluate the quantitativeness of the volumetric mass-density data. Moreover, we propose an algorithm (VortRem) for the removal of phase vortexes, a type of artifact that frequently occurs in holographic methods. VortRem and the results presented here may be fundamental for extending the applicability of this emerging technique to quantitative three-dimensional characterization studies of light as well as dense samples down to the nanoscale.