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

Area of Science:

• Electron microscopy
• Materials science
• Imaging techniques

Background:

• Ptychography in electron microscopy typically uses scanning transmission electron microscopy (STEM) with a focused probe.
• This focused probe is scanned across the sample, which can be time-consuming and limit field of view.

Purpose of the Study:

• To develop a new ptychography approach using wide-field, structured illumination instead of a focused scanning probe.
• To demonstrate the capability of this new method for imaging large areas and reconstructing quantitative electron phase images.

Main Methods:

• Implementation of near-field ptychography utilizing a structured illumination pattern generated by an etched Silicon Nitride window.
• Acquisition of near-field diffraction patterns from the illuminated sample area.

Main Results:

• Successful imaging of fields of view up to 100 μm².
• Reconstruction of quantitative electron phase images using a minimal number of diffraction patterns (as few as nine).

Conclusions:

• The developed near-field ptychography approach offers a viable alternative to traditional STEM-ptychography.
• This technique significantly expands the field of view and reduces data requirements for quantitative phase imaging in electron microscopy.