Compensation of surface plasmon loss by gain in dielectric medium

It has been experimentally shown that absorption loss in metal, which causes damping of localized surface plasmons (SPs) and propagating surface plasmon polaritons (SPPs), can be compensated by optical gain in dye-doped dielectric media adjacent to a metallic surface. In particular, (i) six-fold increase of Rayleigh scattering caused by an enhancement of SP resonance in aggregated metallic nanoparticles, (ii) significant elongation of the propagation length of SPPs by gain, and (iii) stimulated emission of SPPs has been demonstrated. The obtained results pave the road to many applications of nanoplasmonics and metamaterials.