"Laser-manipulation of matter waves: the fine structure constant and phase-contrast electron microscopy," by Holger Müller (UC Berkeley)

Date: 
Tuesday, December 4, 2018 - 2:30pm to 3:30pm
Series: 
AMO Seminars

Abstract:

Manipulating matter waves with lasers enables precise measurements and powerful instruments with uses across the sciences.  Measurements of the fine-structure constant are powerful tests of the consistency of theory and experiment in physics. Using the recoil frequency of cesium-133 atoms in a matter-wave interferometer, we recorded a measurement of the fine-structure constant α = 1/137.035999046(27) at 0.20 parts per billion accuracy using multiphoton interactions such as Bragg diffraction and Bloch oscillations. Comparison with Penning trap measurements of the electron gyromagnetic anomaly via the Standard Model of particle physics has implications for dark-sector candidates and electron substructure. We will close with an outlook on future applications of matterwave interferometry.

Improving the image contrast in transmission electron microscopy of biological macromolecules could help determine protein structures that currently elude reconstruction due to small size or inherent structural heterogeneity. Contrast can be increased by inserting a Zernike phase plate into the electron stream to retard the transmitted wave relative to the scattered wave, but charging effects have hindered various efforts to develop such a phase plate. Here, we demonstrate phase contrast imaging based on electron retardation by a continuous-wave laser field. Images of the intra-cavity light wave captured by an electron interferometer provide direct evidence of coherent electron retardation.

Event Attachments: 
Location: 
PAB 4-330