X Ray Near Field Holography
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X Ray Near Field Holography Beyond Idealized Assumptions Of The Probe
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Author : Johannes Hagemann
language : en
Publisher: Göttingen University Press
Release Date : 2017
X Ray Near Field Holography Beyond Idealized Assumptions Of The Probe written by Johannes Hagemann and has been published by Göttingen University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with categories.
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.
X Ray Near Field Holography
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Author : Johannes Hagemann
language : en
Publisher:
Release Date : 2017
X Ray Near Field Holography written by Johannes Hagemann and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with categories.
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 absorption-based 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 r...
Phase Retrieval For Object And Probe In The Optical Near Field
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Author : Anna-Lena Robisch
language : en
Publisher: Göttingen University Press
Release Date : 2016
Phase Retrieval For Object And Probe In The Optical Near Field written by Anna-Lena Robisch and has been published by Göttingen University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with categories.
Lensless, holographic X-ray microscopy is a non-invasive imaging technique that provides resolution on the nanometer scale. Therefore, a divergent, coherent and especially clean wave front impinging on the sample is needed. Yet, focusing X-rays by even the most advanced X-ray mirrors causes so called figure errors of high spatial frequency content. The results are strongly deteriorated intensity profiles that are often even more pronounced than the holographic image of the sample itself. A common strategy to compensate these figure errors is to divide the hologram by the pure intensity profile of the beam (the so called flat field). However, this division is only valid in the limiting case of an illumination focused down to a point source. In reality, as a consequence of a fi nite spot size, one has to accept a loss in resolution when performing the flat field correction. An approach different from the described straightforward procedure is necessary. Here, the simultaneous reconstruction of object and probe is proposed using holograms which were not flat field corrected before phase retrieval. To this end, a method has been developed that allows simultaneously reconstructing object and probe in amplitude and phase from holographic intensity recordings. The experimental way of proceeding was mainly inspired by well-established holographic full-field X-ray imaging techniques that require holograms defocused to different degrees. Consequently, the conclusion seems reasonable that diversity in the optical near-field arises mainly from variation of the propagation distance of light. This so called longitudinal diversity is used to properly phase the transmission function of the sample of interest. The algorithmic strategy of simultaneous phase retrieval for object and probe draws on far-field ptychography where lateral translations of the sample create diverse diffraction patterns. In view of the need for longitudinal diversity realized by shifts of the sample along the optical axis, ptychography has been generalized and adapted for the optical near-field. Hence, translations of the sample in all three dimensions of space need to be exploited to collect enough information about object and probe such that both can be reconstructed simultaneously in amplitude and phase. Concepts have been put into practice by simulations as well as by experiments with coherent visible light and hard X-rays from synchrotron sources. The presented approach offers the opportunity to perform high resolution imaging, to be extended to tomography and to be adapted to super-resolution experiments.
Nanoscale Photonic Imaging
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Author : Tim Salditt
language : en
Publisher: Springer Nature
Release Date : 2020-06-09
Nanoscale Photonic Imaging written by Tim Salditt and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020-06-09 with Science categories.
This open access book, edited and authored by a team of world-leading researchers, provides a broad overview of advanced photonic methods for nanoscale visualization, as well as describing a range of fascinating in-depth studies. Introductory chapters cover the most relevant physics and basic methods that young researchers need to master in order to work effectively in the field of nanoscale photonic imaging, from physical first principles, to instrumentation, to mathematical foundations of imaging and data analysis. Subsequent chapters demonstrate how these cutting edge methods are applied to a variety of systems, including complex fluids and biomolecular systems, for visualizing their structure and dynamics, in space and on timescales extending over many orders of magnitude down to the femtosecond range. Progress in nanoscale photonic imaging in Göttingen has been the sum total of more than a decade of work by a wide range of scientists and mathematicians across disciplines, working together in a vibrant collaboration of a kind rarely matched. This volume presents the highlights of their research achievements and serves as a record of the unique and remarkable constellation of contributors, as well as looking ahead at the future prospects in this field. It will serve not only as a useful reference for experienced researchers but also as a valuable point of entry for newcomers.
Advancing The Characterization Of Neuronal Cyto Architecture By X Ray Phase Contrast Tomography
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Author : Marina Eckermann
language : en
Publisher: Universitätsverlag Göttingen
Release Date : 2021
Advancing The Characterization Of Neuronal Cyto Architecture By X Ray Phase Contrast Tomography written by Marina Eckermann and has been published by Universitätsverlag Göttingen this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021 with categories.
To bring physiology and pathology of the human brain into better micro-anatomical and histological context, studies with different methodologies are required. Established techniques such as electron microscopy or histology show limitations in view of invasiveness, labor-intense and artifact-prone sample preparation, as well as an adequate ratio between resolution and volume throughput. For this reason, X-ray phase-contrast tomography (PC-CT) has been proposed as a three-dimensional non-destructive imaging technique, which requires less effort in sample preparation and can assess larger volumes. Furthermore, it offers quantitative electron density based contrast even for unstained tissue. Up to now, however, PC-CT studies fell short in number of samples, so that structural alterations caused by neurodegenerative diseases cannot be distinguished from physiological inter-subject variations. In this thesis, the scalability of PC-CT with respect to the required number of samples and resolution-to-volume-throughput is demonstrated, and the methodology is advanced with respect to data acquisition, processing and segmentation. In addition to the human cerebellum, cortex and hippocampus are studied. Concerning quantification and analysis of PC-CT data, this work introduces optimal transport analysis to obtain quantitative metrics of the cyto-architecture and to identify changes due to neurodegenerative diseases. For the case of Alzheimer’s disease, this workflow reveals a yet undescribed compactification of granular cells in the human hippocampus. This thesis also provides optimized configurations to study neural tissues with laboratory instrumentation, and – finally – provides new correlative imaging approaches, in particular with scanning electron microscopy.
A Study On New Approaches In Coherent X Ray Microscopy Of Biological Specimens
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Author : Klaus Giewekemeyer
language : en
Publisher: Universitätsverlag Göttingen
Release Date : 2011
A Study On New Approaches In Coherent X Ray Microscopy Of Biological Specimens written by Klaus Giewekemeyer and has been published by Universitätsverlag Göttingen this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with categories.
The use of coherent x rays for microscopic imaging has seen a rapid and ongoing development within the past decade, driven by an increasing availability of highly brilliant and coherent sources worldwide. Accordingly, novel methods have been developed, which replace the microscope‘s objective lens by a numerical reconstruction scheme. The aim of the present work is to study how very recent experimental and algorithmic developments in the field can be implemented towards a highly sensitive and fully quantitative microscopy method for imaging of biological cells. To this end, different experimental approaches are studied, based on coherent far-field as well as near-field diffraction. At first, an application of the novel ptychographic imaging method to single biological cells is presented. In particular, it is demonstrated how weakly scattering biological specimens can be imaged with fully quantitative density contrast. Alongside, a sueccessful extension of the method towards soft x-ray energies is described.In the second part of the work it is shown how x-ray waveguides can be used as a point source for propagation-based microscopy of single cells in the hard x-ray regime. The specifically devised iterative reconstruction scheme allows for full quantitativity and high sensitivity and thus enables an application to single biological cells. The work contains a thorough introduction into the x-ray optical methods applied and aims at a useful and self-contained overview on aspects of signal and Fourier theory relevant for the used numerical propagation schemes.
Handbook Of Materials For String Musical Instruments
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Author : Voichita Bucur
language : en
Publisher: Springer
Release Date : 2016-08-29
Handbook Of Materials For String Musical Instruments written by Voichita Bucur and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016-08-29 with Technology & Engineering categories.
This book addresses core questions about the role of materials in general and of wood in particular in the construction of string instruments used in the modern symphony orchestra – violins, violas, cellos and basses. Further attention is given to materials for classical guitars, harps, harpsichords and pianos. While some of the approaches discussed are traditional, most of them depend upon new scientific approaches to the study of the structure of materials, such as for example wood cell structure, which is visible only using modern high resolution microscopic techniques. Many examples of modern and classical instruments are examined, together with the relevance of classical techniques for the treatment of wood. Composite materials, especially designed for soundboards could be a good substitute for some traditional wood species. The body and soundboard of the instrument are of major importance for their acoustical properties, but the study also examines traditional and new wood species used for items such as bows, the instrument neck, string pegs, etc. Wood species’ properties for musical instruments and growth origins of woods used by great makers such as Antonio Stradivari are examined and compared with more recently grown woods available to current makers. The role of varnish in the appearance and acoustics of the final instrument is also discussed, since it has often been proposed as a ‘secret ingredient’ used by great makers. Aspects related to strings are commented.As well as discussing these subjects, with many illustrations from classical and contemporary instruments, the book gives attention to conservation and restoration of old instruments and the physical results of these techniques. There is also discussion of the current value of old instruments both for modern performances and as works of art having great monetary value.The book will be of interest and value to researchers, advanced students, music historians, and contemporary string instrument makers. Musicians in general, particularly those playing string instruments, will also find its revelations fascinating. It will also attract the attention of those using wood for a variety of other purposes, for its use in musical instruments uncovers many of its fundamental features. Professor Neville H. FletcherAustralian National University, Canberra
X Ray Phase Contrast Imaging Using Near Field Speckles
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Author : Marie-Christine Zdora
language : en
Publisher: Springer Nature
Release Date : 2021-02-16
X Ray Phase Contrast Imaging Using Near Field Speckles written by Marie-Christine Zdora and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-02-16 with Science categories.
This thesis presents research on novel X-ray imaging methods that improve the study of specimens with small density differences, revealing their inner structure and density distribution. Exploiting the phase shift of X-rays in a material can significantly increase the image contrast compared to conventional absorption imaging. This thesis provides a practical guide to X-ray phase-contrast imaging with a strong focus on X-ray speckle-based imaging, the most recently developed phase-sensitive method. X-ray speckle-based imaging only requires a piece of abrasive paper in addition to the standard X-ray imaging setup. Its simplicity and robustness combined with the compatibility with laboratory X-ray sources, make it an ideal candidate for wide user uptake in a range of fields. An in-depth overview of the state of the art of X-ray speckle-based imaging and its latest developments is given in this thesis. It, furthermore, explores a broad range of applications, from X-ray optics characterisation, to biomedical imaging for 3D virtual histology and geological studies of volcanic rocks, demonstrating is promising potential. Moreover, the speckle-based technique is placed in the context of other phase-sensitive X-ray imaging methods to assist in the choice of a suitable method, hence serving as a guide and reference work for future users.
Three Dimensional Holographic Imaging
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Author : Chung J. Kuo
language : en
Publisher: John Wiley & Sons
Release Date : 2003-04-08
Three Dimensional Holographic Imaging written by Chung J. Kuo and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2003-04-08 with Technology & Engineering categories.
A comprehensive survey of the state of the art in 3-D holographic imaging techniques and applications This book introduces the general concepts of both real-time and non-real-time 3-D holographic imaging techniques for scientific and engineering applications. It offers readers a fundamental understanding of the concepts of 3-D holographic imaging as well as cost-effective design and implementation. World-renowned experts in the field provide in-depth discussion of the following topics: * Holograms of real and virtual point trajectories * Self-stabilized real-time holographic recording * Principles and applications of optical scanning holography * Tangible, dynamic holographic images * Holographic laser radar * Preliminary studies on compression of interference patterns in electronic holography * Photoelectronic principles, components, and applications * Design and implementation of computer-generated hologram and diffractive optical elements * Catastrophe analysis as the basis for visual perception Three-Dimensional Holographic Imaging is the most complete survey available of the fundamental topics in the field, ideal for electrical engineers, optical scientists, and advanced CAD/CAM systems engineers engaged in the design and construction of advanced imaging systems.
Hard X Ray Microscopy Enhanced By Coherent Image Reconstruction
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Author : Jakob Soltau
language : en
Publisher: Universitätsverlag Göttingen
Release Date : 2022
Hard X Ray Microscopy Enhanced By Coherent Image Reconstruction written by Jakob Soltau and has been published by Universitätsverlag Göttingen this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022 with categories.
X-ray microscopy is used to study the structure, dynamics and bulk properties of matter with high spatial resolutions. It is widely applied, from physics and chemistry to material and life sciences. In the past two decades, progress in X-ray microscopy was driven either by improvements in X-ray optics or by improvements in the image reconstruction by using algorithms as computational lenses. In this work both approaches are combined to exploit the advantages of X-ray imaging with a large numerical aperture and the advantages of coherent image reconstruction. It is shown that a combined X-ray microscope using both, advanced optics and algorithms, is neither limited by flawed optics nor by constraints imposed by reconstruction algorithms, which enables to go beyond current limits in resolution and applications. The thesis is structured in four parts. In the first part hard X-ray lenses, so called multilayer zone plates, are simulated to investigate volume diffraction effects within the multilayer structure, and to study the potential for smaller focus sizes and higher efficiencies. In the second part, the multilayer zone plates are characterized and implemented in an X-ray microscope. In the third part, a new imaging scheme is presented, which combines in-line holography and coherent diffractive imaging. This method overcomes the current resolution limit of in-line holography and can achieve super-resolution with respect to the numerical aperture of the illuminating beam. Finally, in the fourth part a multilayer zone plate is used as an objective lens with a known transfer function in a novel coherent full-field imaging experiment based on iterative phase retrieval, for high resolution and quantitative contrast.