Probing InAs quantum dot states with surface plasmon polaritons

Abstract

When placed near a thin metallic film, excitons in a quantum dot (QD) decay into surface plasmon polaritons (SPPs), guided modes of light confined at the interface of the metal/dielectric. It was reported that the interaction of SPPs with excitons in a QD may give rise to a modification in the photoluminescence (PL) spectra of the exciton energy levels, however the mechanism that explains this modification remains unclear. We propose a new methodology to excite many energy levels in an exciton by placing the QDs near a metallic array of slits fabricated onto a thin metallic gold (Au) film. By changing the position under the array where the QDs are excited we can resolve between the many energy levels. The unique features of the PL spectra obtained are the result of the strong electromagnetic field (EMF), the increase in the local density of states (LDOS) and the mesoscopic effects attributed to the gradient of the SPP field near the QDs.