Universal Scaling of Surface Plasmon Modes

Plasmons are collective electron oscillations, preferentially excitable in metals and can be seen as propagating density waves of conduction electrons. They are whether of bulk type and propagate within the material (“3D plasmon”), or along the metal’s surface (2D or surface plasmon). In nanooptics surface plasmons are of special interest, because they can be excited optically (generated at optical frequencies) and show confinement into areas smaller than the wavelength of light, which causes a strong increase of the electric field intensities. This and the ability of surface plasmons to transform an optical signal into a quasi 2D state, also described as “flat light”, make them a promising candidate for a multitude of applications.