Active plasmonics: Surface plasmon interactions with optical emitters

Abstract—The interaction between surface plasmons and op-tical emitters is fundamentally important for engineering appli-cations, especially surface plasmon amplification and controlled spontaneous emission. We investigate these phenomena in an active planar metal-film system comprising InGaN/GaN quantum wells and a silver film. First, we present a detailed study of the propa-gation and amplification of surface plasmon polaritons (SPPs) at visible frequencies. In doing so, we propose a multiple quantum well structure and present quantum well gain coefficient calcula-tions accounting for SPP polarization, line broadening due to ex-citon damping, and particularly, the effects of finite temperature. Second, we show that the emission of an optical emitter into various channels (surface plasmons, lossy surface waves, and free radia-tion) can be precisely controlled by strategically positioning the emitters. Together, these could provide a range of photonic devices (for example, surface plasmon amplifiers, nanolasers, nanoemit-ters, plasmonic cavities) and a foundation for the study of cavity quantum electrodynamics associated with surface plasmons. Index Terms—Amplification, multiple quantum wells (MQWs), Purcell factor, spontaneous emission, surface plasmons. I