Résumé:

We study the effect of confinement on surface plasmons in a planar cavity with a wall coated with a lossy metal as well as with two walls coated with a lossy metal. The dispersion curves are studied in details and explicit relations are obtained locally for the first case. It is shown that modes strongly concentrated at the air-metal interface can be obtained. Finally, we discuss the modes of the lossy waveguide, in particular their completeness.