This work proposes a double quantum dot (DQD) system, with a wetting layer (WL) is included, to study the negative refractive index (NRI) under the application of the electric fields: pump, probe, and fields between WL-QD state, in addition to the magnetic field. The density matrix theory is used to write the equation of motion and an orthogonalized plane wave is used between WL-QD states. The results show that the DQD system exhibit NRI ordinarily until with pump and probe signals, only, due to the manipulation between states. A high NRI corresponding to neglected absorption is obtained under applied electric fields between QD-QD, the conduction (CB) and valence bands (VB) WL-QD fields. It is shown that the main requirement in increasing NRI is the high electric gain connected with a low magnetic one. This can be obtained under five applied electric fields in addition to a high VB WL-QD electric field. Neglecting WL reduces NRI by ~ 16 times. In single QD, the NRI is very small compared with DQD.

中文翻译：

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双量子点系统中的负折射

这项工作提出了一个双量子点 (DQD) 系统，包括一个润湿层 (WL)，以研究在电场应用下的负折射率 (NRI)：泵、探针和 WL-QD 状态之间的场，除了磁场。密度矩阵理论用于编写运动方程，并在 WL-QD 状态之间使用正交平面波。结果表明，DQD 系统通常表现出 NRI，直到有泵和探测信号，仅由于状态之间的操纵。在 QD-QD、导带 (CB) 和价带 (VB) WL-QD 场之间的外加电场下获得对应于忽略吸收的高 NRI。结果表明，增加 NRI 的主要要求是高电增益和低磁增益。除了高 VB WL-QD 电场外，这还可以在五个外加电场下获得。忽略 WL 将 NRI 降低约 16 倍。在单 QD 中，NRI 与 DQD 相比非常小。