Enhanced Imaging in Scanning Transmission X-Ray Microscopy Assisted by Ptychography.

Scanning transmission X-ray microscopy (STXM) is a direct imaging technique with nanoscale resolution. But its resolution is limited by the spot size on the sample, i.e., by the manufacturing technique of the focusing element. As an emerging high-resolution X-ray imaging technique, ptychography utilizes highly redundant data from overlapping scans as well as phase retrieval algorithms to simultaneously reconstruct a high-resolution sample image and a probe function. In this study, we designed an accurate reconstruction strategy to obtain the probe spot with the vibration effects being eliminated, and developed an image enhancement technique for STXM by combining the reconstructed probe with the deconvolution algorithm. This approach significantly improves the resolution of STXM imaging and can break the limitation of the focal spot on STXM resolution when the scanning step size is near or below the spot size, while the data processing time is much shorter than that of ptychography. Both simulations and experiments show that this approach can be applied to STXM data at different energies and different scan steps using the same focal spot retrieved via ptychography.