Efficient large field of view electron phase imaging using near-field electron ptychography with a diffuser

Frederick Allars; Peng-Han Lu; Maximilian Kruth; Rafal E Dunin-Borkowski; John M Rodenburg; Andrew M Maiden

doi:10.1016/j.ultramic.2021.113257

Efficient large field of view electron phase imaging using near-field electron ptychography with a diffuser

Ultramicroscopy. 2021 Dec:231:113257. doi: 10.1016/j.ultramic.2021.113257. Epub 2021 Mar 11.

Authors

Frederick Allars¹, Peng-Han Lu², Maximilian Kruth², Rafal E Dunin-Borkowski³, John M Rodenburg¹, Andrew M Maiden⁴

Affiliations

¹ Department of Electronic and Electrical Engineering, Sir Frederick Mappin Building, University of Sheffield, S3 7HQ, United Kingdom.
² Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Juelich, 52425 Juelich, Germany; RWTH Aachen University, 52074 Aachen, Germany.
³ Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Juelich, 52425 Juelich, Germany.
⁴ Department of Electronic and Electrical Engineering, Sir Frederick Mappin Building, University of Sheffield, S3 7HQ, United Kingdom. Electronic address: a.maiden@sheffield.ac.uk.

PMID: 33773842
DOI: 10.1016/j.ultramic.2021.113257

Abstract

Most implementations of ptychography on the electron microscope operate in scanning transmission (STEM) mode, where a small focussed probe beam is rapidly scanned across the sample. In this paper we introduce a different approach based on near-field ptychography, where the focussed beam is replaced by a wide-field, structured illumination, realised through a purpose-designed etched Silicon Nitride window. We show that fields of view as large as 100 μm² can be imaged using the new approach, and that quantitative electron phase images can be reconstructed from as few as nine near-field diffraction pattern measurements.

Keywords: Electron microscopy; Phase retrieval; Ptychography.