Controlling optical properties and drag of photon and surface plasmon polaritons in triple quantum dot molecules and dots-metal plasmonic interface via tunneling-assisted quantum coherence

Abstract

Optical properties of surface plasmon polaritons (SPPs) and drag of photon and SPPs attracted great attention owing to multi-fold potential fundamental and technological implications. In this paper, we investigate the nature of light propagation, optical properties of probe field and SPPs and drag of photon and SPPs in a four-level triple quantum dot molecule (TQDM) well and a dots-metallic plasmonic interface (DMPI). The quantum coherence in TQDM and coupled DMPI interface is achieved via interbands tunneling-assisted quantum coherence namely- classical electromagnetically induced transparency (EIT) and plasmonic induced transparency (PIT). In contrast to earlier studies, herein we employed Drude-model type dielectric constant of metal with inclusion of size-dependent correction term to account for the reduced electron relaxation rate near the thin metal interface. In particular, after solving the master density-matrix equation of the quantum dot system for the eigenvalues, we interpreted the calculated theoretical results on light dragging and optical properties of probe field and SPPs via tunneling-assisted dressed-state picture of EIT/PIT in the proposed TQDM system and DMPI interface. The tunneling parameter considerably tuned the nature of light propagation from subluminal to superluminal and vice versa, optical properties and drag of photon and SPPs. The maximum positive (negative) value of the group index for photon is of order 3.68×106 (2.685×106) while for SPPs it is of order 3×105. The maximum value of lateral drag for photon and SPPs is ±5×10-2m and ±1.173×10-3m, respectively. The calculated propagation length and wavelength for SPPs are 6.25×10-7m and 3.78×10-7 m which correspond to the quality factor of 10.38.