Interpretable and efficient contrast in scanning transmission electron microscopy with a diffraction grating beamsplitter

TL;DR

This paper introduces a novel phase measurement technique in scanning transmission electron microscopy using a nanofabricated diffraction grating, offering improved interpretability and potential resolution over existing methods.

Contribution

The authors develop and demonstrate a diffraction grating beamsplitter method for phase imaging in STEM, enhancing interpretability and resolution compared to traditional phase-contrast techniques.

Findings

Phase measurement is more interpretable without an off-axis reference.

Resolution could surpass that of off-axis electron holography.

Experimental results agree with simulations.

Abstract

Efficient imaging of biomolecules, 2D materials and electromagnetic fields depends on retrieval of the phase of transmitted electrons. We demonstrate a method to measure phase in a scanning transmission electron microscope using a nanofabricated diffraction grating to produce multiple probe beams. The measured phase is more interpretable than phase-contrast scanning transmission electron microscopy techniques without an off-axis reference wave, and the resolution could surpass that of off-axis electron holography. We apply the technique to image nanoparticles, carbon sub- strates and electric fields. The contrast observed in experiments agrees well with contrast predicted in simulations.