X Ray Near Field Holography Beyond Idealized Assumptions Of The Probe

Author : Johannes Hagemann
Publisher : Göttingen University Press
Page : 152 pages
File Size : 45,6 Mb
Release : 2017
Category : Electronic
ISBN : 9783863953324

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X-Ray Near-Field Holography: Beyond Idealized Assumptions of the Probe by Johannes Hagemann Pdf

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.

Author : Johannes Hagemann
Publisher : Unknown
Page : 128 pages
File Size : 51,8 Mb
Release : 2017
Category : Electronic
ISBN : OCLC:1010940490

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X-ray Near-field Holography by Johannes Hagemann Pdf

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...

Author : Tim Salditt,Alexander Egner,D. Russell Luke
Publisher : Springer Nature
Page : 634 pages
File Size : 55,8 Mb
Release : 2020-06-09
Category : Science
ISBN : 9783030344139

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Nanoscale Photonic Imaging by Tim Salditt,Alexander Egner,D. Russell Luke Pdf

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.

Author : Anna-Lena Robisch
Publisher : Göttingen University Press
Page : 178 pages
File Size : 51,9 Mb
Release : 2016
Category : Electronic
ISBN : 9783863952525

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Phase retrieval for object and probe in the optical near-field by Anna-Lena Robisch Pdf

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.

Author : A. Richard Thompson,James M. Moran,George Warner Swenson
Publisher : Wiley-Interscience
Page : 568 pages
File Size : 52,6 Mb
Release : 1986-04-28
Category : Nature
ISBN : UOM:39015018289580

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Interferometry and Synthesis in Radio Astronomy by A. Richard Thompson,James M. Moran,George Warner Swenson Pdf

A unified description of the theory and practice of radio interferometry and synthesis mapping techniques as they apply to astronomy and geology. Beginning with an historical review, it goes on to provide a detailed description of all aspects of radio inferometry, from basic principles through instrumental design to data reduction. Over 450 original papers and monographs are cited.

Author : Frances M. Ross
Publisher : Cambridge University Press
Page : 529 pages
File Size : 53,7 Mb
Release : 2017
Category : Science
ISBN : 9781107116573

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Liquid Cell Electron Microscopy by Frances M. Ross Pdf

2.6.2 Electrodes for Electrochemistry

Author : Herbert Hopster,Hans Peter Oepen
Publisher : Springer Science & Business Media
Page : 324 pages
File Size : 42,9 Mb
Release : 2006-03-30
Category : Technology & Engineering
ISBN : 9783540266419

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Magnetic Microscopy of Nanostructures by Herbert Hopster,Hans Peter Oepen Pdf

A comprehensive collection of overview articles on novel microscopy methods for imaging magnetic structures on the nanoscale. Written by leading scientists in the field, the book covers synchrotron based methods, spin-polarized electron methods, and scanning probe techniques. It constitutes a valuable source of reference for graduate students and newcomers to the field.

Author : Earl G. Williams
Publisher : Academic Press
Page : 324 pages
File Size : 43,5 Mb
Release : 1999-06-16
Category : Mathematics
ISBN : 0127539603

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Fourier Acoustics by Earl G. Williams Pdf

Fourier Acoustics develops the theory of sound radiation completely from the viewpoint of Fourier analysis. This powerful perspective of sound radiation provides the reader with a comprehensive and practical understanding which will enable him or her to diagnose and solve sound and vibration problems of the 21st century. As a result of this perspective, Fourier Acoustics is able to present thoroughly and simply, for the first time in book form, the theory of nearfield acoustical holography, an important technique which has revolutionized the measurement of sound. The book includes: The physics of wave propagation and sound radiation in homogeneous media Acoustics, such as radiation of sound, and radiation from vibrating surfaces Inverse problems, for example the thorough development of the theory of nearfield acoustical holography Mathematics of specialized functions, such as spherical harmonics The author is an internationally recognized acoustician whose pioneering research in the field of nearfield acoustical holography has impacted acoustics research and development throughout the world. Dr. Williams' research has been formally recognized by NRL as one of its most innovative technologies over the past 75 years. Relying little on material outside the book, Fourier Acoustics will be invaluable as a graduate level text as well as a reference for researchers in academia and industry. The book is unique amongst acoustics texts, it is well illustrated and it includes exercises to enforce the theory.

Author : Norbert G. H. Meyendorf,Peter B. Nagy,Stanislav I. Rokhlin
Publisher : Springer Science & Business Media
Page : 435 pages
File Size : 53,6 Mb
Release : 2013-11-21
Category : Science
ISBN : 9783662089880

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Nondestructive Materials Characterization by Norbert G. H. Meyendorf,Peter B. Nagy,Stanislav I. Rokhlin Pdf

With an emphasis on aircraft materials, this book describes techniques for the material characterization to detect and quantify degradation processes such as corrosion and fatigue. It introduces readers to these techniques based on x-ray, ultrasonic, optical and thermal principles and demonstrates the potential of the techniques for a wide variety of applications concerning aircraft materials, especially aluminum and titanium alloys. The advantages and disadvantages of various techniques are evaluated.

Author : Oliver Bimber,Ramesh Raskar
Publisher : CRC Press
Page : 386 pages
File Size : 45,7 Mb
Release : 2005-08-08
Category : Computers
ISBN : 9781439864944

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Spatial Augmented Reality by Oliver Bimber,Ramesh Raskar Pdf

Like virtual reality, augmented reality is becoming an emerging platform in new application areas for museums, edutainment, home entertainment, research, industry, and the art communities using novel approaches which have taken augmented reality beyond traditional eye-worn or hand-held displays. In this book, the authors discuss spatial augmented r

Author : Horaƫiu Năstase
Publisher : Cambridge University Press
Page : 457 pages
File Size : 40,6 Mb
Release : 2015-09-10
Category : Science
ISBN : 9781107085855

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Introduction to AdS/CFT Correspondence by Horaƫiu Năstase Pdf

A pedagogical and self-contained introduction to AdS/CFT correspondence aimed at graduate students and researchers across theoretical physics.

Author : Qi Zhong
Publisher : Göttingen University Press
Page : 164 pages
File Size : 51,5 Mb
Release : 2017
Category : Electronic
ISBN : 9783863953256

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Advanced x-ray multilayer waveguide optics by Qi Zhong Pdf

The aim of this thesis was to design novel waveguide structures, and to analyze them in view of complex phenomena of near-field propagation. For this purpose, experimental far-field measurements were used in combination with finite-difference simulations and phase retrieval methods. Two novel structures have been designed, fabricated and characterized: the waveguide array (WGA), yielding several waveguided beams in transmission, and multi-guide resonate beam couplers (RBCs), tailored to yield two or several reflected beams. Two novel structures have been designed, fabricated and characterized: the WGA, yielding several waveguided beams in transmission, and multi-guide RBCs, tailored to yield two or several reflected beams. The WGA and the multi-guide RBCs are not only distinct in the coupling geometry. A major difference is related to the fact that the WGA principle is based on the separation (non coupling) of the different transmitted wavelets, while the RBC functions are based on a strong coupling of guided radiation in several layers.

Author : Harvey H. Hubbard
Publisher : Unknown
Page : 620 pages
File Size : 51,5 Mb
Release : 1991
Category : Aerodynamic noise
ISBN : STANFORD:36105024722329

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Aeroacoustics of Flight Vehicles by Harvey H. Hubbard Pdf

Author : Theodore G. Rochow,Paul A. Tucker
Publisher : Springer Science & Business Media
Page : 462 pages
File Size : 53,5 Mb
Release : 2013-06-29
Category : Science
ISBN : 9781489915139

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Introduction to Microscopy by Means of Light, Electrons, X Rays, or Acoustics by Theodore G. Rochow,Paul A. Tucker Pdf

Following three printings of the First Edition (1978), the publisher has asked for a Second Edition to bring the contents up to date. In doing so the authors aim to show how the newer microscopies are related to the older types with respect to theoretical resolving power (what you pay for) and resolution (what you get). The book is an introduction to students, technicians, technologists, and scientists in biology, medicine, science, and engineering. It should be useful in academic and industrial research, consulting, and forensics; how ever, the book is not intended to be encyclopedic. The authors are greatly indebted to the College of Textiles of North Carolina State University at Raleigh for support from the administration there for typing, word processing, stationery, mailing, drafting diagrams, and general assistance. We personally thank Joann Fish for word process ing, Teresa M. Langley and Grace Parnell for typing services, Mark Bowen for drawing graphs and diagrams, Chuck Gardner for photographic ser vices, Deepak Bhattavahalli for his work with the proofs, and all the other people who have given us their assistance. The authors wish to acknowledge the many valuable suggestions given by Eugene G. Rochow and the significant editorial contributions made by Elizabeth Cook Rochow.

Author : Norbert Stribeck
Publisher : Springer Science & Business Media
Page : 251 pages
File Size : 42,9 Mb
Release : 2007-05-16
Category : Technology & Engineering
ISBN : 9783540698562

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X-Ray Scattering of Soft Matter by Norbert Stribeck Pdf

This manual is a useful ready-reference guide to the analytical power of modern X-ray scattering in the field of soft matter. The author describes simple tools that can elucidate the mechanisms of structure evolution in the studied materials, and follows this up with a step-by-step guide to more advanced methods. Data analysis based on clear, unequivocal results is rendered simple and straightforward – with a stress on careful planning of experiments and adequate recording of all required data.