Copper plasmonics with excitons

We investigate the propagation of surface plasmons in a thin layer of copper surrounded by copper oxide ${\mathrm{Cu}}_{2}\mathrm{O}$. It is shown that particularly strong excitons in ${\mathrm{Cu}}_{2}\mathrm{O}$ can have a considerable impact on plasmon propagation, providing many opportunities for plasmon-exciton and plasmon-plasmon interactions. It is demonstrated that by the use of a sufficiently thin metal layer, one can excite the so-called long range plasmons, which can overcome the inherently high ohmic losses of Cu as compared to the usual plasmonic metals such as silver. Analytical results are confirmed by numerical calculations.