Commentary: Plasmons go quantum

Plasmons are collective oscillations of electron gas: loosely speaking they happen when all the electrons move together in the same fashion. They can exist in the bulk of metals but also at their surfaces. In that case, they are called Surface Plasmons. As a matter of fact, surface plasmons have been known for years: scientific studies involving plasmons date back to the beginning of the twentieth century [1]. Due to the oscillations of the electrons, to these oscillations is associated an electromagnetic field. Conversely, an incoming electromagnetic field exerts a coulomb force on electrons that are forced to oscillate. This oscillation results in turn into a scattered field. This interaction can be confined on a surface and lead to a propagating field along this surface: it is then called a Surface Plasmon Polariton (SPP). Surface plasmons polaritons are really what is of interest for telecommunications and information technology [2].