University PhD Dissertation Defense of Stewart A. Koppell

Department of Applied Physics
PhD Dissertation Defense
 
 
New Optics for Low Damage Electron Microscopy
 
 
Stewart A. Koppell, PhD Candidate
Research Advisor: Professor Mark Kasevich
 
Friday December 4, 2020 @09:30 AM Pacific Time
 
 
Zoom link:
https://stanford.zoom.us/j/96751286267
Email mariaf67 [at] stanford.edu (mariaf67[at]stanford[dot]edu) for password
 
 
Abstract
While transmission electron microscopes are in principle capable of atomic resolution, the practical resolution limit for many samples of critical interest (i.e. biological molecules, polymers, battery materials) is determined by beam-induced damage. This leads to a dose-limited resolution far inferior to the resolution limit set by diffraction and aberrations. Multi-Pass Transmission Electron Microscopy (MPTEM) is a new technique for improving dose-limited resolution. I will motivate MPTEM with theory and simulation and present a detailed design of the novel optical elements which enable this protocol. I will also discuss the design of a programmable electron phase plate, which controls electron wavefronts and enables a variety of new measurement techniques. Finally, I will describe a new approach to understanding phase imaging for strongly scattering samples, which will be critical for extracting the maximum possible information from a multi-pass measurement.