Radiative-Decay Engineering: Surface Plasmon-Coupled Emission

Abstract

In the preceding chapter we described the use of metallic particles to modify emission. This was accomplished by interaction of the excited dipoles of the fluorophore with oscillating electrons in a nearby metallic surface. We used the term “metal” to describe such surfaces. We described how a fluorophore near a metal can have a different radiative-decay rate. This is an unusual effect because this rate does not change substantially when a fluorophore is in different environments. In this chapter we describe another phenomenon that occurs when a fluorophore is near a metal. Under certain circumstances a fluorophore can couple with a continuous metallic surface to create groups of oscillating electrons called surface plasmons. If the metal film is thin and on an appropriate substrate the plasmons radiate their energy into the substrate. We call this phenomenon surface plasmon-coupled emission (SPCE).1 There are numerous potential applications for this phenomenon that efficiently collects the emission and transforms it into directional radiation.