  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.
