The passage of a free-electron beam through a nano-hole in a periodically layered metal/dielectric structure creates a new type of tuneable, nanoscale radiation source - a 'light-well'. With a lateral size of just a few hundred nanometers, and an emission intensity of ~200 W/cm^2 such light-wells may be employed in nanophotonic circuits as chip-scale sources, or in densely packed ensembles for optical memory and display applications.
@article{arxiv.0907.2143,
title = {The light-well: A tuneable free-electron light source on a chip},
author = {G. Adamo and Y. H. Fu and C-M. Wang and K. F. MacDonald and D. P. Tsai and F. J. Garcia de Abajo and N. I. Zheludev},
journal= {arXiv preprint arXiv:0907.2143},
year = {2010}
}