You are invited to our next Imaging and Optical Physics Seminar, to be held on May 11th at 1pm on Zoom.
Our two speakers are Joanne Etheridge from the Monash Centre for Electron Microscopy, speaking on "Imaging with symmetry at the picometre scale' and Timur Gureyev from the University of Melbourne, speaking on "Differential Holographic Tomography for atomic-resolution electron imaging". Please find abstracts for their talks below.
To connect on the day, please click this URL:
Presenter: Joanne Etheridge
Imaging with symmetry at the picometre scale
An “image” is a representation of an object, providing information about its form and structure. In many imaging systems, image contrast is generated when the object alters the wavelength, amplitude and/or phase of the probing radiation. In this talk, I will discuss a different approach to image formation where contrast is generated when the object alters the symmetry of the probing radiation. We will consider the case when the probe is a spherical electron wave-field focussed to a point smaller than an atom and is raster-scanned across the object - a scenario that can be executed in a scanning transmission electron microscope. Due to the strength of the Coulomb interaction between the probing electron and the specimen, and the consequent multiple, dynamical scattering, these images are acutely sensitive to changes in specimen symmetry at the picometre scale. This provides a different mechanism for imaging atomic-scale features in condensed matter, particularly where symmetry or symmetry-breaking plays a significant role.
Presenter: Timur Gureyev
Differential Holographic Tomography for atomic-resolution electron imaging