Researchers in Spain and the US have made a system composed of a quantum light emitter placed between two metallic nanoparticles that could be exploited to make novel information devices of the future with non-linear optical response. The interaction between matter and light has been intensively studied over the last 10 years and scientists have succeeded in making devices capable of controlling this interaction. Devices made of metallic nanostructures can focus and trap light into tiny regions, much smaller than the wavelength of light and can also strongly interact with other photonic elements, such as quantum emitters. Quantum plasmonics is a new area of study where by the quantum behaviour of these structures becomes important by nanofabrication.

A quantum emitter placed in the gap between two metallic nanoparticles having non-linear behaviour exhibits fermionic character. Plasmons are collective oscillations of electrons and propagate on the surface of a metal. They can interact strongly with light. Depending on the initial state of the quantum emitter it is possible to switch the coupling between the emitter and the plasmons (on the metallic nanoparticles) on and off. There is a strong electromagnetic field that exists in the gap of the dimmer. The researchers formulated a model to describe many other plasmonic-exciton interactions in systems such as plasmonic transistors, modulators and quantum information devices. The researchers believe that it may even be used to help design novel optical devices, such as optical switchers.