Large Field-of-View Ptychographic Reconstruction of Tilted Surfaces with Adaptive Free Path

In atomic-resolution imaging of solids, the sample surface is frequently tilted. This tilt causes the electron beam to traverse varying distances in the vacuum prior to entering the sample at different locations. This phenomenon markedly degrades image quality, especially over large fields of view in ptychography. To tackle this issue, adaptive free-path ptychography (AFP) is developed. This method is capable of decoupling the free path from the 4D data during the ptychographic reconstruction process. It enables the determination of the rumpling of 2D materials, the surface morphology of nanomaterials, and the acquisition of images of a large field-of-view, thereby facilitating a more comprehensive understanding of the microstructure of materials. Moreover, AFP holds great promise for promoting the widespread application of ptychographic tomography in the analysis of planar samples.