Lohse, Leon Merten

[["dc.bibliographiccitation.firstpage","41932"],["dc.bibliographiccitation.issue","25"],["dc.bibliographiccitation.journal","Optics Express"],["dc.bibliographiccitation.volume","29"],["dc.contributor.author","Soltau, Jakob"],["dc.contributor.author","Lohse, Leon Merten"],["dc.contributor.author","Osterhoff, Markus"],["dc.contributor.author","Salditt, Tim"],["dc.date.accessioned","2021-12-02T15:07:31Z"],["dc.date.available","2021-12-02T15:07:31Z"],["dc.date.issued","2021-12-01"],["dc.description.abstract","Recent progress in nanofabrication, namely of multilayer optics, and the constructionof coherent hard x-ray sources has enabled high resolution x-ray microscopy with large numericalaperture optics for small focal spot sizes. Sub-10 nm and even sub-5 nm focal spot sizes havealready been achieved using multilayer optics such as multilayer Laue lenses and multilayerzone plates. However these optics can not be described by the kinematic theory given theirextreme aspect-ratio between the depth (thickness) and the layer width. Moreover, the numericalsimulation of these optics is challenging, and the absence of an accessible numerical frameworkinhibits further progress in their design and utilization. Here, we simulate the propagation of x-raywavefields within and behind optical multilayer elements using a finite-difference propagationmethod. We show that the method offers high accuracy at reasonable computational cost. Weinvestigate how small focal spot sizes and highest diffraction efficiency of multilayer opticscan be achieved, considering volume diffraction effects such as waveguiding and Pendellösung.Finally, we show the simulation of a novel imaging scheme, allowing for a detailed study ofimage formation and the development of customized phase retrieval schemes."],["dc.identifier.doi","10.1364/OE.445300"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/94973"],["dc.relation.issn","1094-4087"],["dc.relation.workinggroup","RG Salditt (Structure of Biomolecular Assemblies and X-Ray Physics)"],["dc.title","Finite-difference propagation for the imulation of x-ray multilayer optics"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1413"],["dc.bibliographiccitation.issue","7"],["dc.bibliographiccitation.journal","Chem Catalysis"],["dc.bibliographiccitation.lastpage","1426"],["dc.bibliographiccitation.volume","1"],["dc.contributor.author","Werny, Maximilian J."],["dc.contributor.author","Valadian, Roozbeh"],["dc.contributor.author","Lohse, Leon Merten"],["dc.contributor.author","Robisch, Anna-Lena"],["dc.contributor.author","Zanoni, Silvia"],["dc.contributor.author","Hendriksen, Coen"],["dc.contributor.author","Weckhuysen, Bert M."],["dc.contributor.author","Meirer, Florian"],["dc.date.accessioned","2022-08-26T08:30:45Z"],["dc.date.available","2022-08-26T08:30:45Z"],["dc.date.issued","2021"],["dc.identifier.doi","10.1016/j.checat.2021.10.008"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/113255"],["dc.language.iso","en"],["dc.relation.issn","2667-1093"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.subject.gro","x-ray scattering"],["dc.title","X-ray nanotomography uncovers morphological heterogeneity in a polymerization catalyst at multiple reaction stages"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","32871"],["dc.bibliographiccitation.issue","18"],["dc.bibliographiccitation.journal","Optics Express"],["dc.bibliographiccitation.lastpage","32886"],["dc.bibliographiccitation.volume","30"],["dc.contributor.author","Huhn, Simon"],["dc.contributor.author","Lohse, Leon Merten"],["dc.contributor.author","Lucht, Jens"],["dc.contributor.author","Salditt, Tim"],["dc.creator.author","Simon Huhn"],["dc.creator.author","Leon Merten Lohse"],["dc.creator.author","Jens Lucht"],["dc.creator.author","Tim Salditt"],["dc.date.accessioned","2022-08-26T08:37:51Z"],["dc.date.available","2022-08-26T08:37:51Z"],["dc.date.issued","2022-08-24"],["dc.description.abstract","Based on phase retrieval, lensless coherent imaging and in particular holography offers quantitative phase and amplitude images. This is of particular importance for spectral ranges where suitable lenses are challenging, such as for hard x-rays. Here, we propose a phase retrieval approach for inline x-ray holography based on Tikhonov regularization applied to the full nonlinear forward model of image formation. The approach can be seen as a nonlinear generalization of the well-established contrast transfer function (CTF) reconstruction method. While similar methods have been proposed before, the current work achieves nonlinear, constrained phase retrieval at competitive computation times. We thus enable high-throughput imaging of optically strong objects beyond the scope of CTF. Using different examples of inline holograms obtained from illumination by a x-ray waveguide-source, we demonstrate superior image quality even for samples which do not obey the assumption of a weakly varying phase. Since the presented approach does not rely on linearization, we expect it to be well suited also for other probes such as visible light or electrons, which often exhibit strong phase interaction."],["dc.identifier.doi","10.1364/OE.462368"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/113256"],["dc.language.iso","en"],["dc.relation","SFB 1456: Mathematik des Experiments: Die Herausforderung indirekter Messungen in den Naturwissenschaften"],["dc.relation","SFB 1456 | Cluster C | C03: Intensity correlations in diffraction experiments: convolution, reconstruction and information"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Salditt (Structure of Biomolecular Assemblies and X-Ray Physics)"],["dc.rights","CC BY 4.0"],["dc.title","Fast algorithms for nonlinear and constrained phase retrieval in near-field X-ray holography based on Tikhonov regularization"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]