Probing InAs quantum dot states with surface plasmon polaritons

TL;DR

This paper introduces a novel method to excite multiple exciton energy levels in InAs quantum dots using surface plasmon polaritons near a metallic slit array, revealing complex interactions affecting photoluminescence spectra.

Contribution

It proposes a new technique to selectively excite exciton states in quantum dots via SPPs, enhancing understanding of their interaction mechanisms.

Findings

Resolved multiple exciton energy levels by varying QD position.

Observed modifications in PL spectra due to strong EMF and LDOS effects.

Identified mesoscopic effects from SPP field gradients.

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.