X-ray ptychography using a distant analyzer

Ptychography has offered unparalleled high resolution in hard X-ray imaging. However, the imaging quality relies on the interaction between the object and the illumination to be well described by a mathematical model in the reconstruction algorithm. Here, we demonstrate at X-ray wavelengths a method that allows for reconstruction of the object exit wavefield without the need for the knowledge of this interaction. The incident field interacts with the object, and the exit wavefield propagates freely to the plane of an analyzer. As we translate the analyzer and measure diffraction patterns, the propagated wavefield can be reconstructed and the object exit wavefield determined by numerical backpropagation. The method broadens the impact and application of ptychography as it offers information inaccessible to conventional ptychography as well as working distances of tens of millimeters. (C) 2016 Optical Society of America