Light Well: A Tunable Free-Electron Light Source on a Chip

Abstract

The passage of a free-electron beam through a nanohole in a periodically layered metal-dielectric structure creates a new type of tunable, nanoscale radiation source—a “light well”. In the reported demonstration, tunable light is generated at an intensity of $\sim 200\mathrm{W}/{\mathrm{cm}}^2$ as electrons with energies in the 20–40 keV range are injected into gold-silica well structures with a lateral size of just a few hundred nanometers.