Tunable Ampere phase plate for low dose imaging of biomolecular complexes

TL;DR

This paper introduces a tunable, support-free phase plate for transmission electron microscopy that uses magnetic fields generated by current-carrying wires to enhance contrast in imaging biological specimens.

Contribution

It presents a novel magnetic phase plate device that is tunable and support-free, validated through experiments, theory, and simulations for improved biological imaging.

Findings

Successful experimental validation of the phase shift

Enhanced contrast in biological specimen imaging

Theoretical and simulation support for device effectiveness

Abstract

A novel device that can be used as a tunable support-free phase plate for transmission electron microscopy of weakly scattering specimens is described. The device relies on the generation of a controlled phase shift by the magnetic field of a segment of current-carrying wire that is oriented parallel or antiparallel to the electron beam. The validity of the concept is established using both experimental electron holographic measurements and a theoretical model based on Ampere's law. Computer simulations are used to illustrate the resulting contrast enhancement for studies of biological cells and macromolecules.