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/cm2 such light-wells may be employed in nanophotonic circuits as chip-scale sources, or in densely packed ensembles for optical memory and display applications.
We provide the first proof-of-concept demonstration of a tuneable, electron-beam-driven, nanoscale radiation source in which light is generated as free-electrons travel down a ‘light-well’ – a nano-hole through a stack of alternating metal and dielectric layers. Near-infrared emission is demonstrated in the present case but the concept may readily be scaled to other wavelength ranges by varying the periodicity of the structure. The simplicity and nanoscale dimensions of the lightwell geometry make it a potentially important device for future integrated nanophotonic circuit, optical memory and display applications where it may be driven by the kinds of microscopic electron sources already developed for ultrahigh-frequency nanoelectronics and next generation flat-panel displays