  We report the suppression of loss of surface plasmon polariton propagating at
the interface between silver film and optically pumped polymer with dye. Large
magnitude of the effect enables a variety of applications of "active"
nanoplasmonics. The experimental study is accompanied by the development of the
analytical description of the phenomenon and the solution of the controversy
regarding the direction of the wavevector of a wave with a strong evanescent
component in an active medium.

Optics