Hagemann, Johannes

[["dc.bibliographiccitation.firstpage","11552"],["dc.bibliographiccitation.issue","10"],["dc.bibliographiccitation.journal","Optics Express"],["dc.bibliographiccitation.lastpage","11569"],["dc.bibliographiccitation.volume","22"],["dc.contributor.author","Hagemann, Johannes"],["dc.contributor.author","Robisch, Anna-Lena"],["dc.contributor.author","Luke, D. R."],["dc.contributor.author","Homann, C."],["dc.contributor.author","Hohage, Thorsten"],["dc.contributor.author","Cloetens, Peter"],["dc.contributor.author","Suhonen, H."],["dc.contributor.author","Salditt, Tim"],["dc.date.accessioned","2017-09-07T11:46:15Z"],["dc.date.available","2017-09-07T11:46:15Z"],["dc.date.issued","2014"],["dc.description.abstract","We illustrate the errors inherent in the conventional empty beam correction of full field X-ray propagation imaging, i.e. the division of intensities in the detection plane measured with an object in the beam by the intensity pattern measured without the object, i.e. the empty beam intensity pattern. The error of this conventional approximation is controlled by the ratio of the source size to the smallest feature in the object, as is shown by numerical simulation. In a second step, we investigate how to overcome the flawed empty beam division by simultaneous reconstruction of the probing wavefront (probe) and of the object, based on measurements in several detection planes (multi-projection approach). The algorithmic scheme is demonstrated numerically and experimentally, using the defocus wavefront of the hard X-ray nanoprobe setup at the European Synchrotron Radiation Facility (ESRF). (C) 2014 Optical Society of America"],["dc.identifier.doi","10.1364/OE.22.011552"],["dc.identifier.fs","604845"],["dc.identifier.gro","3142122"],["dc.identifier.isi","000336957700017"],["dc.identifier.pmid","24921276"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/12635"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/4789"],["dc.language.iso","en"],["dc.notes.intern","WoS Import 2017-03-10 / Funder: [SFB 755]"],["dc.notes.intern","Merged from goescholar"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","final"],["dc.notes.submitter","PUB_WoS_Import"],["dc.relation.issn","1094-4087"],["dc.relation.orgunit","Institut für Numerische und Angewandte Mathematik"],["dc.relation.orgunit","Fakultät für Physik"],["dc.relation.orgunit","Fakultät für Mathematik und Informatik"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Salditt (Structure of Biomolecular Assemblies and X-Ray Physics)"],["dc.rights","Goescholar"],["dc.rights.uri","https://goescholar.uni-goettingen.de/licenses"],["dc.subject.gro","x-ray imaging"],["dc.title","Reconstruction of wave front and object for inline holography from a set of detection planes"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","13973"],["dc.bibliographiccitation.issue","13"],["dc.bibliographiccitation.journal","Optics Express"],["dc.bibliographiccitation.lastpage","13989"],["dc.bibliographiccitation.volume","25"],["dc.contributor.author","Hagemann, Johannes"],["dc.contributor.author","Salditt, Tim"],["dc.date.accessioned","2017-10-24T13:00:40Z"],["dc.date.accessioned","2021-10-11T11:35:06Z"],["dc.date.available","2017-10-24T13:00:40Z"],["dc.date.available","2021-10-11T11:35:06Z"],["dc.date.issued","2017"],["dc.description.abstract","We propose a reconstruction scheme for hard x-ray inline holography, a variant of propagation imaging, which is compatible with imaging conditions of partial (spatial) coherence. This is a relevant extension of current full-field phase contrast imaging, which requires full coherence. By the ability to reconstruct the coherent modes of the illumination (probe), as demonstrated here, the requirements of coherence filtering could be relaxed in many experimentally relevant settings. The proposed scheme is built on the mixed-state approach introduced in [Nature494, 68 (2013)], combined with multi-plane detection of extended wavefields [Opt. Commun.199, 65 (2001), Opt. Express22, 16571 (2014)]. Notably, the diversity necessary for the reconstruction is generated by acquiring measurements at different defocus positions of the detector. We show that we can recover the coherent mode structure and occupancy numbers of the partial coherent probe. Practically relevant quantities as the transversal coherence length can be computed from the reconstruction in a straightforward way."],["dc.description.sponsorship","Open-Access-Publikationsfonds 2017"],["dc.identifier.doi","10.1364/OE.25.013973"],["dc.identifier.gro","3142470"],["dc.identifier.pmid","28788984"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/14797"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/90727"],["dc.language","eng"],["dc.language.iso","en"],["dc.notes.intern","Migrated from goescholar"],["dc.notes.status","final"],["dc.relation.issn","1094-4087"],["dc.relation.orgunit","Fakultät für Physik"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Salditt (Structure of Biomolecular Assemblies and X-Ray Physics)"],["dc.rights","Goescholar"],["dc.rights.access","openAccess"],["dc.rights.uri","https://goedoc.uni-goettingen.de/licenses"],["dc.subject","X-ray imaging; Coherence; Phase retrieval"],["dc.subject.ddc","530"],["dc.subject.gro","x-ray optics"],["dc.subject.gro","x-ray imaging"],["dc.title","Reconstructing mode mixtures in the optical near-field"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","3468"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Nature Communications"],["dc.bibliographiccitation.volume","12"],["dc.contributor.author","Vaßholz, Malte"],["dc.contributor.author","Hoeppe, H. P."],["dc.contributor.author","Hagemann, Johannes"],["dc.contributor.author","Rosselló, J. M."],["dc.contributor.author","Osterhoff, Markus"],["dc.contributor.author","Mettin, Robert"],["dc.contributor.author","Kurz, Thomas"],["dc.contributor.author","Schropp, A."],["dc.contributor.author","Seiboth, F."],["dc.contributor.author","Schroer, C. G."],["dc.contributor.author","Scholz, M."],["dc.contributor.author","Möller, J."],["dc.contributor.author","Hallmann, J."],["dc.contributor.author","Boesenberg, U."],["dc.contributor.author","Kim, C."],["dc.contributor.author","Zozulya, A."],["dc.contributor.author","Lu, W."],["dc.contributor.author","Shayduk, R."],["dc.contributor.author","Schaffer, R."],["dc.contributor.author","Madsen, A."],["dc.contributor.author","Salditt, Tim"],["dc.date.accessioned","2021-06-08T12:44:14Z"],["dc.date.available","2021-06-08T12:44:14Z"],["dc.date.issued","2021-06-08"],["dc.description.abstract","Cavitation bubbles can be seeded from a plasma following optical breakdown, by focusing an intense laser in water. The fast dynamics are associated with extreme states of gas and liquid, especially in the nascent state. This offers a unique setting to probe water and water vapor far-from equilibrium. However, current optical techniques cannot quantify these early states due to contrast and resolution limitations. X-ray holography with single X-ray free-electron laser pulses has now enabled a quasi-instantaneous high resolution structural probe with contrast proportional to the electron density of the object. In this work, we demonstrate cone-beam holographic flash imaging of laser-induced cavitation bubbles in water with nanofocused X-ray free-electron laser pulses. We quantify the spatial and temporal pressure distribution of the shockwave surrounding the expanding cavitation bubble at time delays shortly after seeding and compare the results to numerical simulations."],["dc.description.sponsorship","Open-Access-Publikationsfonds 2021"],["dc.identifier.doi","10.1038/s41467-021-23664-1"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/87172"],["dc.relation.issn","2041-1723"],["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.subject.gro","x-ray imaging"],["dc.title","Pump-probe X-ray holographic imaging of laser-induced cavitation bubbles with femtosecond FEL pulses"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.seriesnr","24"],["dc.contributor.author","Hagemann, Johannes"],["dc.date.accessioned","2018-05-03T10:47:50Z"],["dc.date.available","2018-05-03T10:47:50Z"],["dc.date.issued","2017"],["dc.description.abstract","All images are flawed, no matter how good your lenses, mirrors etc. are. Especially in the hard X-ray regime it is challenging to manufacture high quality optics due to the weak interaction of multi-keV photons with matter. This is a tremendous challenge for obtaining high resolution quantitative X-ray microscopy images. In recent years lensless phase contrast imaging has become an alternative to classical absorptionbased imaging methods. Without any optics, the image is formed only by the free space propagation of the wave field. The actual image has to be formed posteriori by numerical reconstruction methods. Advanced phasing methods enable the experimentalist to recover a complex valued specimen from a single or a set of intensity measurement. This would be the ideal case - reality teaches us that there are no ideal imaging conditions. Describing, understanding and circumventing these non ideal imaging conditions and their effects on X-ray near-field holographic (NFH) imaging are the leitmotifs for this thesis. In NFH the non ideal conditions manifest themselves in the illuminating wave field or probe. The probe generally does not satisfy the canonical assumptions of fully coherent and monochromatic radiation emitted by a point source. The main results of this thesis are compiled as a collection of publications. An approach is shown to reconstruct the probe of a X-ray nano-focus setup by a series of measurements of the probe at varied Fresnel number. The following chapter presents a study concerning the reconstruction efficiency in terms of resolution for near- and far-field based lensless imaging. In the following, the reconstruction scheme for the probe is extended to incorporate the effects of partial coherence in the near field. This enables the recovery of the modal structure of the probe which yields a full description of its coherence properties. Giving up the assumption of temporal stability due to the stochastic pulses, delivered by X-ray free electron lasers, the reconstruction of probe and specimen must be achieved from a single shot. A suitable scheme for this purpose is proposed in this work."],["dc.format.extent","X, 138"],["dc.identifier.doi","10.17875/gup2017-1055"],["dc.identifier.isbn","978-3-86395-332-4"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?univerlag-isbn-978-3-86395-332-4"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/14536"],["dc.identifier.urn","urn:nbn:de:gbv:7-isbn-978-3-86395-332-4-9"],["dc.language.iso","en"],["dc.notes.intern","TASK GROB-550"],["dc.notes.status","zu prüfen"],["dc.publisher","Universitätsverlag Göttingen"],["dc.publisher.place","Göttingen"],["dc.relation.crisseries","Göttingen Series in X-Ray Physics"],["dc.relation.ispartofseries","Göttingen Series in X-ray Physics; 24"],["dc.rights","CC BY-SA 4.0"],["dc.rights.uri","http://creativecommons.org/licenses/by-sa/4.0/deed.de"],["dc.title","X-Ray Near-Field Holography: Beyond Idealized Assumptions of the Probe"],["dc.type","thesis"],["dc.type.internalPublication","unknown"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","52"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Journal of Synchrotron Radiation"],["dc.bibliographiccitation.lastpage","63"],["dc.bibliographiccitation.volume","28"],["dc.contributor.author","Hagemann, Johannes"],["dc.contributor.author","Vaßholz, Malte"],["dc.contributor.author","Hoeppe, Hannes"],["dc.contributor.author","Osterhoff, Markus"],["dc.contributor.author","Rosselló, Juan M."],["dc.contributor.author","Mettin, Robert"],["dc.contributor.author","Seiboth, Frank"],["dc.contributor.author","Schropp, Andreas"],["dc.contributor.author","Möller, Johannes"],["dc.contributor.author","Hallmann, Jörg"],["dc.contributor.author","Kim, Chan"],["dc.contributor.author","Scholz, Markus"],["dc.contributor.author","Boesenberg, Ulrike"],["dc.contributor.author","Schaffer, Robert"],["dc.contributor.author","Zozulya, Alexey"],["dc.contributor.author","Lu, Wei"],["dc.contributor.author","Shayduk, Roman"],["dc.contributor.author","Madsen, Anders"],["dc.contributor.author","Schroer, Christian G."],["dc.contributor.author","Salditt, Tim"],["dc.date.accessioned","2021-04-14T08:30:07Z"],["dc.date.available","2021-04-14T08:30:07Z"],["dc.date.issued","2021"],["dc.description.abstract","X-ray free-electron lasers (XFELs) have opened up unprecedented opportunities\r\nfor time-resolved nano-scale imaging with X-rays. Near-field propagationbased\r\nimaging, and in particular near-field holography (NFH) in its highresolution\r\nimplementation in cone-beam geometry, can offer full-field views of a\r\nspecimen’s dynamics captured by single XFEL pulses. To exploit this capability,\r\nfor example in optical-pump/X-ray-probe imaging schemes, the stochastic\r\nnature of the self-amplified spontaneous emission pulses, i.e. the dynamics of the\r\nbeam itself, presents a major challenge. In this work, a concept is presented to\r\naddress the fluctuating illumination wavefronts by sampling the configuration\r\nspace of SASE pulses before an actual recording, followed by a principal\r\ncomponent analysis. This scheme is implemented at the MID (Materials Imaging\r\nand Dynamics) instrument of the European XFEL and time-resolved NFH\r\nis performed using aberration-corrected nano-focusing compound refractive\r\nlenses. Specifically, the dynamics of a micro-fluidic water-jet, which is commonly\r\nused as sample delivery system at XFELs, is imaged. The jet exhibits rich\r\ndynamics of droplet formation in the break-up regime. Moreover, pump–probe\r\nimaging is demonstrated using an infrared pulsed laser to induce cavitation and\r\nexplosion of the jet."],["dc.identifier.doi","10.1107/S160057752001557X"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/83114"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-399"],["dc.relation.eissn","1600-5775"],["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.subject.gro","x-ray imaging"],["dc.title","Single-pulse phase-contrast imaging at free-electron lasers in the hard X-ray regime"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","013821"],["dc.bibliographiccitation.firstpage","1"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Physical Review. A"],["dc.bibliographiccitation.lastpage","10"],["dc.bibliographiccitation.volume","91"],["dc.contributor.author","Homann, C."],["dc.contributor.author","Hohage, Thorsten"],["dc.contributor.author","Hagemann, J."],["dc.contributor.author","Robisch, A.-L."],["dc.contributor.author","Salditt, Tim"],["dc.date.accessioned","2015-01-29T09:09:40Z"],["dc.date.accessioned","2021-10-11T11:36:16Z"],["dc.date.available","2015-01-29T09:09:40Z"],["dc.date.available","2021-10-11T11:36:16Z"],["dc.date.issued","2015"],["dc.description.abstract","Extended wavefronts are used for coherent full field imaging of objects based on solving the inverse Fresnel diffraction problem. To this end, the conventional data correction step is given by division of the recorded object image by the intensity pattern of the empty beam. This division of intensities in the detection plane is a rather crude approximation for the separation of the complex valued object and probing fields. Here we present a quantitative error estimate, along with its mathematical proof, and confirm the prediction with numerical simulations. Finally the problem is illustrated with experimental results."],["dc.identifier.doi","10.1103/PhysRevA.91.013821"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/11553"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/90770"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.relation.issn","1094-1622"],["dc.relation.issn","1050-2947"],["dc.relation.orgunit","Fakultät für Physik"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Salditt (Structure of Biomolecular Assemblies and X-Ray Physics)"],["dc.rights","CC BY 3.0"],["dc.rights.access","openAccess"],["dc.rights.uri","https://creativecommons.org/licenses/by/3.0/"],["dc.subject","empty-beam correction; near-field imaging; Validity"],["dc.subject.gro","x-ray imaging"],["dc.title","Validity of the empty-beam correction in near-field imaging"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","987-994"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Journal of Synchrotron Radiation"],["dc.bibliographiccitation.volume","28"],["dc.contributor.author","Osterhoff, Markus"],["dc.contributor.author","Vaßholz, Malte"],["dc.contributor.author","Hoeppe, Hannes Paul"],["dc.contributor.author","Rosselló, Juan Manuel"],["dc.contributor.author","Mettin, Robert"],["dc.contributor.author","Hagemann, Johannes"],["dc.contributor.author","Möller, Johannes"],["dc.contributor.author","Hallmann, Jörg"],["dc.contributor.author","Scholz, Markus"],["dc.contributor.author","Schaffer, Robert"],["dc.contributor.author","Boesenberg, Ulrike"],["dc.contributor.author","Kim, Chan"],["dc.contributor.author","Zozulya, Alexey"],["dc.contributor.author","Lu, Wei"],["dc.contributor.author","Shayduk, Roman"],["dc.contributor.author","Madsen, Anders"],["dc.contributor.author","Salditt, Tim"],["dc.date.accessioned","2021-05-07T07:22:19Z"],["dc.date.available","2021-05-07T07:22:19Z"],["dc.date.issued","2021-05-01"],["dc.description.abstract","Single-pulse holographic imaging at XFEL sources with 1012 photons delivered in pulses shorter than 100 fs reveal new quantitative insights into fast phenomena. Here, a timing and synchronization scheme for stroboscopic imaging and quantitative analysis of fast phenomena on time scales (sub-ns) and length-scales (≲100 nm) inaccessible by visible light is reported. A fully electronic delay-and-trigger system has been implemented at the MID station at the European XFEL, and applied to the study of emerging laser-driven cavitation bubbles in water. Synchronization and timing precision have been characterized to be better than 1 ns."],["dc.identifier.doi","10.1107/S1600577521003052"],["dc.identifier.pmid","33950007"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/84669"],["dc.language.iso","en"],["dc.relation.eissn","1600-5775"],["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.subject.gro","x-ray imaging"],["dc.title","Nanosecond timing and synchronization scheme for holographic pump-probe studies at the MID instrument at European XFEL"],["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","852"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Journal of Synchrotron Radiation"],["dc.bibliographiccitation.lastpage","859"],["dc.bibliographiccitation.volume","27"],["dc.contributor.author","Lohse, Leon Merten"],["dc.contributor.author","Robisch, Anna Lena"],["dc.contributor.author","Töpperwien, Mareike"],["dc.contributor.author","Maretzke, Simon"],["dc.contributor.author","Krenkel, Martin"],["dc.contributor.author","Hagemann, Johannes"],["dc.contributor.author","Salditt, Tim"],["dc.date.accessioned","2020-12-10T18:25:59Z"],["dc.date.available","2020-12-10T18:25:59Z"],["dc.date.issued","2020"],["dc.description.abstract","Propagation-based phase-contrast X-ray imaging is by now a well established imaging technique, which – as a full-field technique – is particularly useful for tomography applications. Since it can be implemented with synchrotron radiation and at laboratory micro-focus sources, it covers a wide range of applications. A limiting factor in its development has been the phase-retrieval step, which was often performed using methods with a limited regime of applicability, typically based on linearization. In this work, a much larger set of algorithms, which covers a wide range of cases (experimental parameters, objects and constraints), is compiled into a single toolbox – the HoloTomoToolbox – which is made publicly available. Importantly, the unified structure of the implemented phase-retrieval functions facilitates their use and performance test on different experimental data."],["dc.identifier.doi","10.1107/S1600577520002398"],["dc.identifier.eissn","1600-5775"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/75904"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.relation.issn","1600-5775"],["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.subject.gro","x-ray imaging"],["dc.subject.gro","biomedical tomography"],["dc.title","A phase-retrieval toolbox for X-ray holography and tomography"],["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","20953"],["dc.bibliographiccitation.issue","18"],["dc.bibliographiccitation.journal","Optics Express"],["dc.bibliographiccitation.lastpage","20968"],["dc.bibliographiccitation.volume","25"],["dc.contributor.author","Hagemann, Johannes"],["dc.contributor.author","Salditt, Tim"],["dc.date.accessioned","2017-11-09T09:39:25Z"],["dc.date.accessioned","2021-10-11T11:31:16Z"],["dc.date.available","2017-11-09T09:39:25Z"],["dc.date.available","2021-10-11T11:31:16Z"],["dc.date.issued","2017"],["dc.description.abstract","We present a phase reconstruction scheme for X-ray near-field holographic imaging based on a separability constraint for probe and object. In order to achieve this, we have devised an algorithm which requires only two measurements - with and without an object in the beam. This scheme is advantageous if the standard flat-field correction fails and a full ptychographic dataset can not be acquired, since either object or probe are dynamic. The scheme is validated by numerical simulations and by a proof-of-concept experiment using highly focused undulator radiation of the beamline ID16a of the European Synchrotron Radiation Facility (ESRF)."],["dc.description.sponsorship","Open-Access-Publikationsfonds 2017"],["dc.identifier.doi","10.1364/OE.25.020953"],["dc.identifier.gro","3142466"],["dc.identifier.pmid","29041506"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/14828"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/90601"],["dc.language","eng"],["dc.language.iso","en"],["dc.notes.intern","Migrated from goescholar"],["dc.notes.status","final"],["dc.relation.issn","1094-4087"],["dc.relation.orgunit","Fakultät für Physik"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Salditt (Structure of Biomolecular Assemblies and X-Ray Physics)"],["dc.rights","Goescholar"],["dc.rights.access","openAccess"],["dc.rights.uri","https://goedoc.uni-goettingen.de/licenses"],["dc.subject","near-field holography"],["dc.subject.ddc","530"],["dc.subject.gro","x-ray imaging"],["dc.title","Divide and update: towards single-shot object and probe retrieval for near-field holography"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","498"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Journal of Synchrotron Radiation"],["dc.bibliographiccitation.lastpage","505"],["dc.bibliographiccitation.volume","24"],["dc.contributor.author","Hagemann, Johannes"],["dc.contributor.author","Robisch, Anna-Lena"],["dc.contributor.author","Osterhoff, Markus"],["dc.contributor.author","Salditt, Tim"],["dc.date.accessioned","2020-11-05T15:05:24Z"],["dc.date.available","2020-11-05T15:05:24Z"],["dc.date.issued","2017"],["dc.description.abstract","In X-ray holographic near-field imaging the resolution and image quality depend sensitively on the beam. Artifacts are often encountered due to the strong focusing required to reach high resolution. Here, two schemes for reconstructing the complex-valued and extended wavefront of X-ray nano-probes, primarily in the planes relevant for imaging (i.e. focus, sample and detection plane), are presented and compared. Firstly, near-field ptychography is used, based on scanning a test pattern laterally as well as longitudinally along the optical axis. Secondly, any test pattern is dispensed of and the wavefront reconstructed only from data recorded for different longitudinal translations of the detector. For this purpose, an optimized multi-plane projection algorithm is presented, which can cope with the numerically very challenging setting of a divergent wavefront emanating from a hard X-ray nanoprobe. The results of both schemes are in very good agreement. The probe retrieval can be used as a tool for optics alignment, in particular at X-ray nanoprobe beamlines. Combining probe retrieval and object reconstruction is also shown to improve the image quality of holographic near-field imaging."],["dc.identifier.doi","10.1107/S160057751700128X"],["dc.identifier.gro","3142476"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/68459"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-352.6"],["dc.notes.status","final"],["dc.relation.eissn","1600-5775"],["dc.relation.issn","1600-5775"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Salditt (Structure of Biomolecular Assemblies and X-Ray Physics)"],["dc.rights","CC BY 2.0"],["dc.subject.gro","x-ray imaging"],["dc.title","Probe reconstruction for holographic X-ray imaging"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","no"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]