2025/07/24 by Varnavides, Georgios, Bekkevold, Julie Marie, Ribet, Stephanie M +3 · 3 citations
#FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Optics (physics.optics)
paper · doi:10.48550/arxiv.2507.18610
Direct ptychography enables the retrieval of information encoded in the phase of an electron wave passing through a thin sample by deconvolving the interference effects of a converged probe with known aberrations. Under the weak phase object approximation, this permits the optimal transfer of information using non-iterative techniques. However, the achievable resolution of the technique is traditionally limited by the probe step size -- setting stringent Nyquist sampling requirements. At the same time, parallax imaging has emerged as a dose-efficient phase-retrieval technique which relaxes sampling requirements and enables scan-upsampling. Here, we formulate parallax imaging as a quadratic approximation to part of the direct ptychography kernel and use this insight to enable upsampling in direct ptychography. We validate our analytical results numerically using simulated and experimental reconstructions.