Coherence properties of the high-energy fourth-generation X-ray synchrotron sources

A genuine representation of the cross-spectral density function as a superposition of mutually uncorrelated, spatially localized modes is applied to model the propagation of spatially partially coherent light beams in X-ray optical systems. Numerical illustrations based on mode propagation with VirtualLab software are presented for imaging systems with ideal and non-ideal grazing-incidence mirrors.

Section: Discussionmentioning

confidence: 99%

Section: The Genuine Field Representationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Genuine-field modeling of partially coherent X-ray imaging systems

Verhoeven

Hellmann²,

Wyrowski

et al. 2020

“…0. A research papers direct calculation of the normalized degree of coherence from the eigenvalues was also derived by Khubbutdinov et al (2019) and is given by…”

Section: Partially Coherent Ptychographymentioning

confidence: 99%

Hard X-ray ptychography for optics characterization using a partially coherent synchrotron source

Moxham

Parsons

Zhou

et al. 2020

Ptychography is a scanning coherent diffraction imaging technique which provides high resolution imaging and complete spatial information of the complex electric field probe and sample transmission function. Its ability to accurately determine the illumination probe has led to its use at modern synchrotrons and free-electron lasers as a wavefront-sensing technique for optics alignment, monitoring and correction. Recent developments in the ptychography reconstruction process now incorporate a modal decomposition of the illuminating probe and relax the restriction of using sources with high spatial coherence. In this article a practical implementation of hard X-ray ptychography from a partially coherent X-ray source with a large number of modes is demonstrated experimentally. A strongly diffracting Siemens star test sample is imaged using the focused beam produced by either a Fresnel zone plate or beryllium compound refractive lens. The recovered probe from each optic is back propagated in order to plot the beam caustic and determine the precise focal size and position. The power distribution of the reconstructed probe modes also allows the quantification of the beams coherence and is compared with the values predicted by a Gaussian–Schell model and the optics exit intensity.

“…Therefore, it is necessary to increase the size of the flat phase distribution area at the focal plane to meet the experimental requirements. Several software packages have been developed for the simulation of partially coherent beams through beamlines, including SRW (Chubar, 2014;Chubar et al, 2011), HYBRID (Shi et al, 2014), SHADOW3 (Sanchez del Rio et al, 2011), PHASE (Bahrdt et al, 2011) and XRT (Sanchez del Rio et al, 2014;Khubbutdinov et al, 2019). Many works have been carried out using these simulation packages for the beamline design.…”

Section: Introductionmentioning

confidence: 99%

Phase analysis for partially coherent light propagating through an optimized aperture in a synchrotron beamline

Ren

Meng

Wang

et al. 2020

The mutual optical intensity propagation of partially coherent light through a beamline is calculated for different aperture sizes and positions. The coherence, intensity and phase distribution can be extracted from the mutual optical intensity. The phase distribution depends on the aperture size and position. The results show that the widest flat phase distribution is obtained at the optimized aperture size and position. The aperture plays a more important role for partially coherent light than for incoherent light. The influence of the aperture size and position on the intensity and spot size at the focal plane is also analyzed. A way to obtain a balance between the flat phase distribution area, spot size and intensity for partially coherent light in the beamline is demonstrated.