Abstract
I predict that a nanoscopic, high-permittivity layer on the surface of a plasmonic metal can cause total external reflection of surface plasmon polaritons (SPPs). Such a layer can be used as a mirror in nanoplasmonics, in particular for resonators of nanolasers and spasers and can also be used in adiabatic nanooptics. I also show that the earlier predicted slow propagating SPP modes, especially those with negative refraction, are highly damped.