Phase Contrast in Scanning Transmission Electron Microscopy with Nanostructured Phase Gratings

ORAL

Abstract

Off-axis electron holography, which uses an electrostatic biprisim to interfere electrons transmitted through a specimen with a reference wave, has for many years been the premier technique for retrieving the phase of electrons. With holography, one can both reconstruct long-range electric and magnetic fields [1], and map the charge distribution in a nanowire [2]. However, the resolution of off-axis electron holography is fundamentally limited because interference fringes are recorded in real space; standard reconstruction of the phase has a resolution on the order of the fringe spacing.

A similar technique is possible in scanning transmission electron microscopy, where the transmitted beam and reference beam are focused, and holograms are recorded in diffraction as the beams are scanned. Resolution is limited only by the size of the focused beams at the specimen. We show that phase retrieval is straightforward and intuitive and present a proof-of-principle demonstration.

[1] O. Matteucci et al., Adv. in Imaging & Elect. Phys. 99, 171 (1997).
[2] Z. Ghan et al., Nano Lett. 16, 3748 (2016).

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Presenters

  • Tyler Harvey

    IV. Physical Institute, University of Göttingen, IV. Physical Institute, Georg-August-Universität

Authors

  • Tyler Harvey

    IV. Physical Institute, University of Göttingen, IV. Physical Institute, Georg-August-Universität

  • Colin Ophus

    National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Lawrence Berkeley National Laboratory, Lawrence Berkeley Natl Lab

  • Fehmi Yasin

    Univ of Oregon, University of Oregon

  • Jordan Chess

    Univ of Oregon

  • Jordan Pierce

    Univ of Oregon

  • Benjamin McMorran

    Univ of Oregon, University of Oregon, Department of Physics, Univ of Oregon