Phase Retrieval For Object And Probe In The Optical Near Field PDF Download
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Author | : Anna-Lena Robisch |
Publisher | : Göttingen University Press |
Total Pages | : 178 |
Release | : 2016 |
Genre | : |
ISBN | : 3863952529 |
Download Phase retrieval for object and probe in the optical near-field Book in PDF, ePub and Kindle
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 | : Anna-Lena Robisch |
Publisher | : |
Total Pages | : |
Release | : 2015 |
Genre | : |
ISBN | : |
Download Phase Retrieval for Object and Probe in the Optical Near-field Book in PDF, ePub and Kindle
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 wavefront 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 profi ...
Author | : Johannes Hagemann |
Publisher | : Göttingen University Press |
Total Pages | : 152 |
Release | : 2017 |
Genre | : |
ISBN | : 3863953320 |
Download X-Ray Near-Field Holography: Beyond Idealized Assumptions of the Probe Book in PDF, ePub and Kindle
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 | : Tim Salditt |
Publisher | : Springer Nature |
Total Pages | : 634 |
Release | : 2020-06-09 |
Genre | : Science |
ISBN | : 3030344134 |
Download Nanoscale Photonic Imaging Book in PDF, ePub and Kindle
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 | : Tim Salditt |
Publisher | : Walter de Gruyter GmbH & Co KG |
Total Pages | : 358 |
Release | : 2017-10-23 |
Genre | : Science |
ISBN | : 3110426692 |
Download Biomedical Imaging Book in PDF, ePub and Kindle
Covering both physical as well as mathematical and algorithmic foundations, this graduate textbook provides the reader with an introduction into modern biomedical imaging and image processing and reconstruction. These techniques are not only based on advanced instrumentation for image acquisition, but equally on new developments in image processing and reconstruction to extract relevant information from recorded data. To this end, the present book offers a quantitative treatise of radiography, computed tomography, and medical physics. Contents Introduction Digital image processing Essentials of medical x-ray physics Tomography Radiobiology, radiotherapy, and radiation protection Phase contrast radiography Object reconstruction under nonideal conditions
Author | : Jinyang Liang |
Publisher | : Springer Nature |
Total Pages | : 697 |
Release | : |
Genre | : |
ISBN | : 3031390628 |
Download Coded Optical Imaging Book in PDF, ePub and Kindle
Author | : Michael Sean Riley |
Publisher | : |
Total Pages | : 250 |
Release | : 2004 |
Genre | : |
ISBN | : |
Download Phase Imaging in the Near Field Book in PDF, ePub and Kindle
The near-field scanning optical microscope (NSOM) is optical microscope that exploits highly localized interactions between a light emitting sub-wavelength aperture and a microscopic object to achieve optical spatial resolution that can approach 30nm. Conventional NSOM methods yield excellent topography and intensity images of opaque materials, where there is significant amplitude alternation to the incident field to provide contrast. Although the light-sample interactions, associated with NSOM, are highly localized, transparent material is either partially resolved or not resolved at all. A conventional NSOM was integrated into an environmentally stabilized Mach-Zehnder interferometer, part optical fiber, and part air, to determine phase changes induced by refractive-index variations in materials. The completed NSOM system allows for simultaneous phase, topography, and intensity imaging of microscopic objects. A 380nm thick transparent pattern photo-resist sample, which consisted of 2um circles on 4um centers, was imaged. The results clearly show an enhanced image quality in the phase image when compared to the intensity image. The resolution was found to be not only function of the aperture size, but a function of the uniformity of the output field emitted by the sub-wavelength aperture and the modulation amplitude of the resonating probe tip-fork system that is employed to maintain the sub-wavelength aperture probe tip in the near-field.
Author | : Peter W. Hawkes |
Publisher | : Springer Nature |
Total Pages | : 1561 |
Release | : 2019-11-02 |
Genre | : Technology & Engineering |
ISBN | : 3030000699 |
Download Springer Handbook of Microscopy Book in PDF, ePub and Kindle
This book features reviews by leading experts on the methods and applications of modern forms of microscopy. The recent awards of Nobel Prizes awarded for super-resolution optical microscopy and cryo-electron microscopy have demonstrated the rich scientific opportunities for research in novel microscopies. Earlier Nobel Prizes for electron microscopy (the instrument itself and applications to biology), scanning probe microscopy and holography are a reminder of the central role of microscopy in modern science, from the study of nanostructures in materials science, physics and chemistry to structural biology. Separate chapters are devoted to confocal, fluorescent and related novel optical microscopies, coherent diffractive imaging, scanning probe microscopy, transmission electron microscopy in all its modes from aberration corrected and analytical to in-situ and time-resolved, low energy electron microscopy, photoelectron microscopy, cryo-electron microscopy in biology, and also ion microscopy. In addition to serving as an essential reference for researchers and teachers in the fields such as materials science, condensed matter physics, solid-state chemistry, structural biology and the molecular sciences generally, the Springer Handbook of Microscopy is a unified, coherent and pedagogically attractive text for advanced students who need an authoritative yet accessible guide to the science and practice of microscopy.
Author | : Guoan Zheng |
Publisher | : Morgan & Claypool Publishers |
Total Pages | : 126 |
Release | : 2016-06-30 |
Genre | : Science |
ISBN | : 1681742748 |
Download Fourier Ptychographic Imaging Book in PDF, ePub and Kindle
This book demonstrates the concept of Fourier ptychography, a new imaging technique that bypasses the resolution limit of the employed optics. In particular, it transforms the general challenge of high-throughput, high-resolution imaging from one that is coupled to the physical limitations of the optics to one that is solvable through computation. Demonstrated in a tutorial form and providing many MATLAB® simulation examples for the reader, it also discusses the experimental implementation and recent developments of Fourier ptychography. This book will be of interest to researchers and engineers learning simulation techniques for Fourier optics and the Fourier ptychography concept.
Author | : D.W. Pohl |
Publisher | : Springer |
Total Pages | : 418 |
Release | : 2011-10-06 |
Genre | : Technology & Engineering |
ISBN | : 9789401119795 |
Download Near Field Optics Book in PDF, ePub and Kindle
Scanning near-field optical microscopy (SNOM, also known as NSOM) is a new local probe technique with a resolving power of 10--50 nm. Not being limited by diffraction, near-field optics (NFO) opens new perspectives for optical characterization and the understanding of optical phenomena, in particular in biology, microelectronics and materials science. SNOM, after first demonstrations in '83/'84, has undergone a rapid development in the past two to four years. The increased interest has been largely stimulated by the wealth of optical properties that can be investigated and the growing importance of characterization on the nanometer scale in general. Examples include the use of fluorescence, birefrigence and plasmon effects for applications in particular in biology, microelectronics and materials science, to name just a few. This volume emerged from the first international meeting devoted exclusively to NFO, and comprises a complete survey of the 1992 activities in the field, in particular the variety of instrumental techniques that are currently being explored, the demonstration of the imaging capabilities as well as theoretical interpretations - a highly nontrivial task. The comprehensive collection of papers devoted to these and related subjects make the book a valuable tool for anybody interested in near-field optics.