Inverse Multislice Ptychography by Layer-wise Optimisation and Sparse Matrix Decomposition

TL;DR

This paper introduces algorithms for inverse multislice ptychography in electron microscopy, enabling the reconstruction of atomic layer potentials and probe estimation, demonstrated on simulated and experimental data.

Contribution

It presents a novel optimization-based approach for inverse multislice ptychography, including layer separation and probe estimation, with practical application to experimental STEM data.

Findings

Unique layer separation possible at low acceleration voltages

Effective probe estimation method introduced

Successful reconstruction on experimental data

Abstract

We propose algorithms based on an optimisation method for inverse multislice ptychography in, e.g. electron microscopy. The multislice method is widely used to model the interaction between relativistic electrons and thick specimens. Since only the intensity of diffraction patterns can be recorded, the challenge in applying inverse multislice ptychography is to uniquely reconstruct the electrostatic potential in each slice up to some ambiguities. In this conceptual study, we show that a unique separation of atomic layers for simulated data is possible when considering a low acceleration voltage. We also introduce an adaptation for estimating the illuminating probe. For the sake of practical application, we finally present slice reconstructions using experimental 4D scanning transmission electron microscopy (STEM) data.