Integrated plasmonic nanodevices

Surface plasmon polaritons (SPPs) are waves that propagate along an interface between a dielectric and a metal if the permittivity of the interface materials satisfies certain conditions. At low frequencies, metals are considered as good conductors; however, they behave very much like dielectrics at optical frequencies [1]. Owing to the presence of intrinsic losses associated with material dispersion, Kramers-Kronig relations suggest that it is necessary to consider both the real and imaginary parts of metal permittivity at optical frequencies.