X Ray Waveguide Optics
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X Ray Waveguide Optics
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Author : Sarah Hoffmann-Urlaub
language : en
Publisher: Göttingen University Press
Release Date : 2017
X Ray Waveguide Optics written by Sarah Hoffmann-Urlaub 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.
Modern x-ray sources and analysis techniques such as lens less imaging combined with phase retrieval algorithms allow for resolving structure sizes in the nanometer range. For this purpose optics have to be employed, ensuring small focal spot dimensions simultaneously with high photon densities. Furthermore, the wave front behind the optics is required to be smooth enabling for high resolution imaging. Combining all these properties, x-ray waveguides are well suited to perform this task, since the intensity distribution behind the guide is restricted in two dimensions serving as a secondary quasi point-source without wave-front aberrations, showing also a high divergence, suitable for resolving fine features. Importantly, the radiation provided by the waveguide reveals a high degree of coherence, required by many imaging techniques. The waveguide itself consists of an air-filled channel embedded in a solid matrix; typical materials are silicon, germanium or quartz. While the entrance area is nano-sized, the channel length is in the millimeter-range, this way posing challenges to fabricate high aspect ratio geometries. Since the functioning of x-ray waveguides is based on the total reflection at small incident angles, the surface roughness of the channel walls must be as low as possible to avoid scattering and hence loss of intensity. To fulfill these demanding conditions, a process scheme involving spin-coating, electron beam lithography, wet development, reactive ion etching and wafer bonding is optimized within this work. To gain deeper insights into the principle of wave guiding finite difference simulations are performed, also opening access for advanced design considerations such as gratings, tapered and curved channels, or beamsplitters, enabling for constructing novel x-ray tools as for example time delay devices or interferometers. Waveguides in all geometries are tested at synchrotron sources, accomplishing new benchmarks in x-ray optical performance. Here, the x-ray beam leaving the channel, propagates out to a pixel array detector in the far-field region. From the recorded data the intensity distribution in the near-field directly behind the waveguide is reconstructed, revealing an outstanding agreement with the simulations and electron micrographs. Since the radiation field of the waveguide is well-characterized and also tunable to meet the requirements of both the measurement setup and the sample, they are suited of a broad field of applications in coherent x-ray imaging.
X Ray Waveguide Optics Beyond Straight Channels
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Author : Sarah Hoffmann-Urlaub
language : en
Publisher:
Release Date : 2016
X Ray Waveguide Optics Beyond Straight Channels written by Sarah Hoffmann-Urlaub and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with categories.
Modern x-ray sources and analysis techniques such as lens less imaging combined with phase retrieval algorithms allow for resolving structure sizes in the nanometerrange. For this purpose optics have to be employed, ensuring small focal spot dimensions simultaneously with high photon densities. Furthermore, the wave front behind the optics is required to be smooth enabling for high-resolution imaging. Combining all these properties, x-ray waveguides are well suited to perform this task, since the intensity distribution behind the guide is restricted in two dimensions serving as a secondary ...
Optimization Of Waveguide Optics For Lensless X Ray Imaging
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Author : Sven Philip Krüger
language : en
Publisher: Universitätsverlag Göttingen
Release Date : 2011
Optimization Of Waveguide Optics For Lensless X Ray Imaging written by Sven Philip Krüger 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.
Lensless x-ray imaging is a promising method to determine the three-dimensional structure of material science and biological specimens at the nanoscale. The development of this technique is strongly related to the optimization of x-ray optics since the image formation and object reconstruction depend significantly on the properties of the illumination wave-field. Waveguide optics act as quasi-point sources and enable the spatial and coherent filtering of x-ray beams. Up to now, x-ray waveguides were severely limited in transmission and flux, restricting their use to high-contrast test structures with moderate resolution and long accumulation times. To overcome these limitations, a novel waveguide design with an optimized refractive index profile is presented which significantly minimizes the absorption of the modes propagating inside the waveguide. Experimental results along with simulations show that these two-component planar x-ray waveguides provide small beam cross-sections along with a high photon flux at the exit. By a serial arrangement of two waveguide slices an optimized illumination source has been developed for high-resolution microscopy, as demonstrated in proof-of-concept imaging experiments.
Advanced X Ray Multilayer Waveguide Optics
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Author : Qi Zhong
language : en
Publisher:
Release Date : 2017
Advanced X Ray Multilayer Waveguide Optics written by Qi Zhong 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.
The aim of this thesis is to demonstrate that x-ray waveguide optics can be gen- eralized from a single guiding film to an array of planar waveguides, enabling more complex and controllable phenomena of field propagation both in partic- ular in the near-field in the vicinity of objects to be probed by coherent imaging. Two advanced x-ray multilayer waveguides (MWGs) structures, i.e. the waveg- uide array (WGA) and the multi-guide resonant beam couplers (RBCs) are de- signed and discussed. Starting from basic theoretical analysis, the structural model of MWGs is built up. Then the MWGs are s...
Advanced X Ray Multilayer Waveguide Optics
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Author : Qi Zhong
language : en
Publisher: Göttingen University Press
Release Date : 2017
Advanced X Ray Multilayer Waveguide Optics written by Qi Zhong 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.
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.
Hard X Ray Waveguide Optics
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Author : Ansgar Jarre
language : en
Publisher:
Release Date : 2005
Hard X Ray Waveguide Optics written by Ansgar Jarre and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005 with categories.
A Dedicated Endstation For Waveguide Based X Ray Imaging
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Author : Sebastian Kalbfleisch
language : en
Publisher: Universitätsverlag Göttingen
Release Date : 2013
A Dedicated Endstation For Waveguide Based X Ray Imaging written by Sebastian Kalbfleisch and has been published by Universitätsverlag Göttingen this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with categories.
Soft X Ray Optics
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Author : Eberhard Spiller
language : en
Publisher: SPIE Press
Release Date : 1994
Soft X Ray Optics written by Eberhard Spiller and has been published by SPIE Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 1994 with Medical categories.
This text describes optics mainly in the 10 to 500 angstrom wavelength region. These wavelengths are 50 to 100 times shorter than those for visible light and 50 to 100 times longer than the wavelengths of medical x rays or x-ray diffraction from natural crystals. There have been substantial advances during the last 20 years, which one can see as an extension of optical technology to shorter wavelengths or as an extension of x-ray diffraction to longer wavelengths. Artificial diffracting structures like zone plates and multilayer mirrors are replacing the natural crystals of x-ray diffraction. Some of these structures can now be fabricated to have diffraction-limited resolution. The new possibilities are described in a simple, tutorial way.
X Ray Waveguides For High Resolution X Ray Analysis
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Author :
language : en
Publisher:
Release Date : 1999
X Ray Waveguides For High Resolution X Ray Analysis written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1999 with categories.
The project goals were to model, synthesize, and characterize thin-film, x-ray waveguide structures to determine whether such nanostructurcs can be fabricated with the precision required for true waveguide operation at x-ray energies. In FY98, we designed, fabricated, and characterized (at the Stanford Synchrotron Radiation Laboratory) optimized. thin-film, x-ray waveguide structures (XWGs) as resonant concentrators of x-rays which may be applied as diffraction-limited, linear x-ray sources. We fabricated nine waveguide structures that were optimized to operate in the cavity modes m = 1,2,3 and tested them at x-ray energies of 6 to 10 keV. The observed performances were compared to the calculations based on the design structures and excellent agreement was demonstrated. This project plan is presented in TABLE 1 that includes all aspects of the development of these unique thin film x-ray optical devices. X-ray waveguide designs were made using a standard x-ray multilayer x-ray optic Fresnel code. Materials were selected on the basis of calculated performance as well as sputter deposition characteristics. Laboratory x-ray reflectivity measurements were made prior to the SSRL experimental run to assess the quality of the samples. Cross-section Transmission Electron Microscopy observations of selected sample were made to enable assessment of the relationship between the design structures and the fabricated structures. The cross-section TEM observations correlated well with the waveguide fabrication parameters supporting the observed agreement between the experimental and calculated grazing incidence reflectivities and fluorescence as functions of both x-ray energy and grazing angle of incidence.
Modern Developments In X Ray And Neutron Optics
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Author : Alexei Erko
language : en
Publisher: Springer
Release Date : 2008-04-01
Modern Developments In X Ray And Neutron Optics written by Alexei Erko and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008-04-01 with Science categories.
This volume describes modern developments in reflective, refractive and diffractive optics for short wavelength radiation. It also covers recent theoretical approaches to modelling and ray-tracing the x-ray and neutron optical systems. It is based on the joint research activities of specialists in x-ray and neutron optics, working together under the framework of the European Programme for Cooperation in Science and Technology (COST, Action P7) in the period 2002-2006.