Recent progress in X-ray ptychography

X-ray ptychography is known as a promising lensless imaging method. Compared with other similar techniques, it can give a rather wide viewing area with the same high-spatial-resolution in nano scale, by combining multiple coherent diffraction measurements from the illumination of several overlapping regions on the sample. However, this apparently has to assume a highly sophisticated scanning/positioning instrumentation. The method may suffer also from partial-coherence effects and fluctuations. Dr. A. Menzel (Paul Scherrer Institut, Switzerland) and his colleagues have recently published an interesting report on fast measurement. The authors discussed ptychographic on-the-fly scans, i.e., collecting diffraction patterns while the sample is scanned with constant velocity. It was found that such a scan can be used as a model for a state mixture of the probing radiation and helps to achieve reliable image recovery. The feasibility of on-the-fly measurements in traditional scanning transmission X-ray microscopy is already known. This time, the research team was successful in applying these to X-ray ptychography, which usually uses reconstruction algorithms assuming diffraction data from a static sample. Such problems were discussed in detail. For more information, see the paper, "On-the-fly scans for X-ray ptychography", P. M. Pelz et al., Appl. Phys. Lett., 105, 251101 (2014).