Tunable surface plasmon polaritons at the surfaces of nanocomposite media

Surface plasmon polaritons (SPPs) at the interfaces of composite media have some important properties not found in conventional SPPs, i.e., SPPs at metal-dielectric interfaces. We present a useful scheme to control basic features of SPPs at the interface between a tripod-type atomic system and a silver-silica (AgSiO2) composite film. There is some interaction between the SPPs at the interface and localized surface plasmons (LSPs) due to Ag-nanoparticles in the composite. We show that the SPP's dispersive properties are strongly dependent on the coherent driving fields applied in the atomic system. Similarly, the filling ratio of the nanoparticles in the composite and the incident wavelength also affect different features of the SPPs. Our model provides more degrees of freedom for tuning the fundamental properties of SPPs at the interfaces associated with composite media.