Scanning diffraction imaging without stable illumination and scan position information (2311.08415v2)

Abstract: Ptychography has become prominent at synchrotron facilities worldwide for characterizing biological and material specimens' topological structures and properties at the nanometer or atomic scale, due to its lens - less, highly quantitative phase imaging. Its high - resolution imaging depends on accurate lateral scan position info, a large overlap ratio, and a stable probe function. But as research moves to atomic scales, meeting these requirements gets harder, often needing high - precision motion control and manual pre - calibration. This paper presents a new imaging framework. By adding a wavefront modulator and a new phase retrieval workflow, it removes the strict requirements of traditional ptychography. Significantly, our method doesn't need pre - calibration of the wavefront modulator. Optical validation showed the deviation between the recovered position and a top - tier motion stage was less than 10 nm. Sub - pixel position accuracy was achievable even with a 13% overlap ratio. In an X - ray experiment with a spatially unstable probe violating the ptychographic model and an 18% overlap ratio, our method simultaneously and quantitatively retrieved beam spatial deviation, scan position, probe function, and sample transmission function. Notably, it measured probe spatial deviations of 500nm along the X - axis and 50nm along the Y - axis, which is not feasible by previous methods. With these experimentally proven advantages, we anticipate our method to be a powerful imaging tool with auto - quantitative calibration of various parameters. It will simplify scanning diffraction microscopy implementation and expand its application scope, especially in nanometer and atomic scale imaging.