The interaction between the localized plasma resonances associated with small metal particles and surface plasmons on a nearby metal-dielectric interface has been observed. Shifts in the surface-plasmon dispersion relation and changes in the effective absorption of the metal particles (Ag-island resonances) resulting from this interaction were measured as a function of the separation $d$ between the two structures. In our geometry, the two excitations are most strongly coupled for a separation $d\cong 25$ nm.

• Received 23 December 1982

DOI:https://doi.org/10.1103/PhysRevB.27.7765