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
Email email@example.com for password
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.