Barwick Lab

Ultrafast electron microscopy for the study of fundamental electron-photon interactions

Google Scholar Page: Brett Barwick

OAM exchange between photons and free electrons:

Experiments have shown that both photons and electrons can carry OAM. These ‘vortex’ beams are interesting for both fundamental and practical reasons. Practical applications for photons that carry OAM include possible increased bandwidth in telecommunications and electrons that carry OAM have an increased sensitivity to magnetic and chiral nanoparticles. Fundamentally quantum mechanics must be used to fully describe how individual photons and electrons can carry quantized amounts of OAM and how that OAM can be exchanged between particles. The first aim of this proposal is to experimentally demonstrate OAM transfer from a laser beam to an electron beam using the Kapitza-Dirac (KD) effect. If successful, we will have demonstrated a new method whereby arbitrary amounts of OAM can be transferred to free electrons which would enhance the sensitivity of ultrafast electron microscopes, electron interferometers and provide a new method of shaping the spatial properties of electron beams.

All optical compression of femtosecond electron pulses

The second aim of this project to use light to compress electron pulses from approximately 1 ps duration, to durations of tens of fs or less. By creating electron pulses with durations on the order of fs the temporal resolution of ultrafast electron microscopes would be improved by more than an order of magnitude, allowing dynamics of systems that have motions too fast for current UEM’s to follow. This will open up the ability to capture dynamics of electronic motion in nanoscale structures advancing our understanding of how nanoplasmonic devices operate in real time.