Speaker
Description
One way of increasing the electron beam brightness in radiofrequency electron guns is by shrinking the photoemission area. Unfortunately, sharp tips are not good candidates to be used in high field RF environments due to field emission and stability issues.
We use Surface Plasmon Polariton wave interference to produce sub-micrometer emission areas. Radially symmetric nano-structured patterns are used to absorb laser light, launch SPPs on the surface of a plasmonic material and concentrate the intensity into sub-wavelength areas, where the large enhancement factor favors electron emission by multi-photon absorption. We have fabricated several sources with electron-beam lithography and focused-ion beam milling. We also spatially mapped the plasmonic resonance modes in these sources with Cathodoluminescence Spectro-microscopy, observing the resonant mode we designed for an 800 nm laser source and studying the influence of fabrication. We will discuss the source design, simulation and measurement of the plasmonic resonance, and current progress on testing their photoemission.
