Our group’s main research is focused on pushing the limits of X-ray imaging techniques towards ever higher resolution and higher contrast sensitivity. In particular, we look at means of using coherence and the related interference and diffraction phenomena as tools to encode efficiently nanometer-scale information from samples of interest. Decoding this information requires sophisticated algorithmic techniques – a specialty of our group.

The main technique applied and investigated in the group is called ptychography.

[2018/08/24] Marie wins the WMI!

Marie-Christine has received the prestigious Werner Mayer-Ilse award for her work on speckle imaging. The prize, awarded every other year during the International X-ray Microscopy conference, rewards the exceptional contributions of young scientists to the field of x-ray microscopy. Related publications: M. Zdora, P. Thibault, T. Zhou, F. J. Koch, J. Romell, S. Sala, A. …

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[21/05/2017] New PRL: UMPA!

A new paper just published in Physical Review Letters introduces our Unified Modulated Pattern Analysis (UMPA) method, which improves speckle tracking techniques by combining multiple measurements to increase resolution and sensitivity. In the paper we demonstrate that the method applies equally well to random (speckles) and regular (e.g. grating) patterns. An implementation of the method …

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[21/12/2016] Our Ptypy paper is out!

Many months of hard work by Björn have paid off: the paper describing our ptypy package has now been published[1]. Beyond the technical descriptions of the package’s inner workings, our paper introduces a new formalism meant to deal with the ever increasing complexity of ptychographic reconstruction algorithms. The package is free of use for academic …

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[01/02/2015] Phys. Rev. Applied: Near-field ptychography on a strongly scattering sample

Near-field ptychography has made its entry a few years ago as a promising alternative to other holographic techniques. The technique combines the concepts and experimental setup of full-field phase-contrast imaging with the robust phase retrieval principles of ptychography. To take one dataset, one simply needs to translate the sample with respect to a structured illumination. …

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[25/10/2014] New open source package

Our ptychography reconstruction package ptypy is now open-source and online! The package has come a long way since its debut at the cSAXS beamline at the Swiss Light Source. The difference map reconstruction algorithm was first implemented in matlab with contributions from Martin Dierolf, Andreas Menzel and Cameron Kewish. Its descendant is still in used …

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