Strong coupling among semiconductor quantum dots induced by a metal nanoparticle

TLDR

The authors aim to demonstrate that surface plasmon polaritons in a metal nanoparticle can mediate strong coupling and entanglement between semiconductor quantum dots by applying a quantum transformation method to the SQD–MNP system. They model a simple SQD–MNP–weak‑light configuration, using the quantum transformation approach to compute exciton energy shifts, modified decay rates, and inter‑dot coupling parameters. The calculations show that two quantum dots become highly entangled via the MNP‑mediated SPP field, achieving high concurrence and indicating a promising route for all‑optical plasmon‑enhanced nanoscale devices.

Abstract

Based on cavity quantum electrodynamics (QED), we investigate the light-matterinteraction between surface plasmon polaritons (SPP) in a metal nanoparticle (MNP)and the excitons in semiconductor quantum dots (SQDs) in an SQD-MNP coupled system.We propose a quantum transformation method to strongly reveal the exciton energyshift and the modified decay rate of SQD as well as the coupling among SQDs. Toobtain these parameters, a simple system composed of an SQD, an MNP, and a weaksignal light is designed. Furthermore, we consider a model to demonstrate thecoupling of two SQDs mediated by SPP field under two cases. It is shown that two SQDscan be entangled in the presence of MNP. A high concurrence can be achieved, which isthe best evidence that the coupling among SQDs induced by SPP field in MNP. Thisscheme may have the potential applications in all-optical plasmon-enhanced nanoscaledevices.