Resonant excitation of confined excitons in nanocrystal quantum dots using surface plasmon-polaritons

Abstract

Surface plasmon-polaritons (SPPs) in a multilayer structure consisting of a metallic film and one or more layers of nanocrystal (NC) quantum dots (QDs) are studied theoretically. It is shown that there is a resonance coupling between the plasmonpolaritons propagating along the metal/NC-layer interface and excitons confined in the dots, which produces a considerable effect on the optical properties of the structure unless the dispersion of the QD size is too large. Using a transfer matrix formalism, multilayer structures consisting of NC composite and metallic films are considered and it is demonstrated that the coupling extends over several layers constituting the structure. It can be explored in order to selectively excite QDs of different size by making a layer-by layer assembled NC planar structure and using an attenuated total reflection (ATR) configuration for the SPPenhanced excitation of the dots. In particular, it opens the possibility to control the relative intensity of light of different color, emitted by the QDs of different size.