Quantum coherence-enhanced optical properties and drag of photons and SPPs in semiconducting quantum dots and resonantly-coupled dot–nanoparticle plasmonic interfaces

Abstract

Enhancing the optical response and Fresnel–Fizeau light dragging in relation to photon plus surface plasmons through various coupled atomic–metal plasmonic interfaces has prompted great interest recently. This is due to the many potential implications of optical properties and drag of light, both from fundamental and technological viewpoints. Herein, we report theoretical results on the quantum-coherence enhanced optical features and light dragging through a well-shaped ensemble of quantum dot molecules (QDMs) and plasmonically coupled dot–(metal)nanoparticle interface. To investigate and tune the required optical properties and light dragging in the superluminal and subluminal regimes, we employed interdot tunneling-driven quantum coherence via electromagnetically-induced transparency (EIT) and plasmonically-induced transparency (PIT). Specifically, in order to determine the required theoretical results, we employed a density-matrix formulation to calculate the complex susceptibility of probe/signal pulse through the proposed QDM. We interpreted the light drag and optical response of probe field and surface plasmons via dressed eigenstates of PIT/EIT and Fano-type quantum interference in the proposed QDMs and dot–metal nanoparticle plasmonic interfaces. Unlike bulk metals, to account for the reduced electron mean free path, hereby, we employed the size-dependent corrected dielectric constant of the Drude model. The maximum predicted value of the wave vector for surface plasmons was 2m−1, which led to greatly enhanced propagation length of the order of 0.25 m. The calculated wavelength was 162.91×10−3 m, corresponding to a quality factor of 9.64.