Hard x-ray nanobeam characterization by coherent diffraction microscopy

Abstract

We have carried out a ptychographic scanning coherent diffraction imaging experiment on a test object in order to characterize the hard x-ray nanobeam in a scanning x-ray microscope. In addition to a high resolution image of the test object, a detailed quantitative picture of the complex wave field in the nanofocus is obtained with high spatial resolution and dynamic range. Both are the result of high statistics due to the large number of diffraction patterns. The method yields a complete description of the focus, is robust against inaccuracies in sample positioning, and requires no particular shape or prior knowledge of the test object.

Soft X-ray spectromicroscopy using ptychography with randomly phased illumination

“…A key requirement is that the illuminated areas overlap substantially, so that iterative algorithms [1][2][3] can successfully reconstruct an image of the specimen, retrieving the amplitude and phase of both the complex sample transmission function and the illuminating probe. At X-ray wavelengths, ptychography has been used to characterize the focusing properties of X-ray optics [4][5][6] , to image interconnects within microchips 7 and to image yeast cells 8 . X-ray ptychography has recently been demonstrated using soft X-rays 9,10 , and has been used with polarized illumination to generate dichroic image contrast from magnetic thin films 11 .…”

Coherent X-ray diffractive imaging on the single-cell-level of microbial samples

“…The reconstruction of the probe can thus be used to analyse the complex eld of the focus [160,265,287].…”

“…More recent ptychographic studies investigate the maximum derivable information from ptychographic data under non-simple experimental conditions for the illuminating wave-eld or the object such as position uncertainties [20,110,182], partial coherence and multiple wavelenghts [15,44,78,299], multiple object planes [181,284] and undersampling of the recorded di racted intensities [71]. In the rst place, however, the probably most important result has been the understanding that the ptychographic method not only is able to solve for the encoded object information but also for the illuminating wave-eld [183,294,296] making ptychography a valuable tool for analysing the wave-elds of X-rays [134,144,159,160,265,268]. In principle, the decoupling of object and illuminating wave-eld makes the retrieved object information free of aberrations.…”

“…An appealing application is the combination of ptychography with the simultaneous recording of uorescence data 25 , which opens the possibility to combine the measurements of mass density with elemental mapping [265]. The ptychographically obtained information about the illuminating wave-eld can also be used by 25 The used set-up at the cSAXS simply did not include a uorescence detector.…”

“…First results using divergent beams have been reported, including nanofocusing refractive X-ray lenses [134,265,266], Fresnel zone plates [143,312,330] and Kirkpatrick-Baez (KB) mirrors [98,143,286,287]. KB mirrors are attractive focusing devices due to their high e ciency at sub 100 nm focusing while providing long working distances of hundreds of millimetres [130, 189, 199 201].…”