Abstract
X-ray ptychography has strongly developed during the last decade and is routinely applied at various synchrotron radiation X-ray sources worldwide.(1-4) The technique is based on the scanning of a sample through a spatially confined and coherent X-ray beam and the recording of far-field diffraction patterns at each scan point.(5, 6) If these diffraction patterns are measured from areas of the sample with a sufficient overlap between adjacent scan points, numerically robust algorithms exist to retrieve structural information of the sample's X-ray transmission function in amplitude and phase.(7, 8) In addition, due to the high degree of overdetermination of the inverse problem, the complex-valued illumination function can be determined at the same time.(9-11) Since the method does not rely on high-performance X-ray optics requiring a large numerical aperture, the spatial resolution is in principle only limited by the number of coherent photons available during the experiment.(12) In this way, the accessible spatial resolution regime often extends beyond limits of current X-ray optics towards the 10nm range in 2D and 3D.13-15