Individual molecules as gates for plasmonic light emission

The ongoing miniaturization of electronic circuitry suggests a similar development for optical elements and light sources. A tunnel current between a fine metal tip and a metal surface generates highly localized optical fields which may propagate as plasmons or emit light, thus forming an innovative optical source on the atomic scale. An individual molecule can be employed as a gate when introduced into the electronic tunnel path. The gating is directly related to the molecular electronic orbitals and may have applications in interfacing electronics and optical sources.