Regensburg 2022 – scientific programme

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 25: Poster

KFM 25.12: Poster

Thursday, September 8, 2022, 15:00–18:00, P2

Phase retrieval for X-ray in-line holographic imaging: beyond the homogeneous object assumption — •Jens Lucht¹, Simon Huhn¹, Leon Merten Lohse^1,2, and Tim Salditt¹ — ¹Institut für Röntgenphysik, Universität Göttingen — ²Deutsches Elektronen-Synchrotron DESY

X-ray lensless near-field holographic imaging offers high resolution 3d imaging with spatial resolution down to the nanometer scale with wide applicability in biomedical imaging and material sciences. To access quantitative images, phase retrieval has to be performed on the recorded Fresnel diffraction patterns. This constitutes an ill-posed inverse problem where several reconstruction methods have been developed. For high resolution synchrotron experiments, computationally efficient algorithms are needed. Widely employed is the computationally efficient contrast transfer function (CTF) method proposed by P. Cloetens two decades ago [P. Cloetens et al., Appl. Phys. Lett. 75, 2912 (1999)], besides more demanding nonlinear Fresnel propagation based methods. The CTF relies upon linearization of the Fresnel propagation. Notwithstanding its tremendous success, CTF-based methods often assume a homogeneous or low absorbing object as prior. We propose a CTF-based scheme that could relax these restriction to applicability while keeping reconstruction stability and computational requirements comparable. First experiments indicate very promising results.