Broadband Ultrafast Photon Source for Interrogation of Optical Cavity Enhanced Electron Emitters
Abstract
The development of high brightness, ultrafast electron sources with low emittance is of core importance for a large array of DOD-relevant applications such as high power microwave devices, space propulsion, electron beam lithography, neutron generation, and free electron lasers. Traditionally, electron sources exploit field emission, thermionic emission, or photoemission, and rely on material properties to enable favorable source characteristics. However, the fundamental understanding of the connection between the material and the performance of these electron sources requires further elucidation. For this purpose, we propose obtaining a femtosecond pulsed laser system capable of outputting an 80 MHz train of pulses with widths of <200 fs across a wavelength range between 205 nm – 4000 nm at high average powers up to 4 W and peak powers up to 300 kW. The output of this laser would be used to study electron emission processes through an on-chip silicon photonics platform that enables efficient and controlled coupling of photons with thermionic, field, and photo-emitters. The proposed system will allow us to study two effects: first, the ultrafast pulse times permit observation of the impulse response of cavity-emitter systems, enabling an experimental measure of the true time response of the system. Second, the wide energy range enables spectroscopic studies of photoemission, photo-enhanced field emission, and photo-enhanced thermionic emission. Through these studies Prof. Kapadia will be able to develop detailed materials models of the interaction between cavities and emitters, elucidating both the optical response as well as the electronic response across a wide range of photon energies and emission mechanisms.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 11, 2018
- Source ID
- FA95501810367
Entities
People
- Rehan Kapadia
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Southern California