Negative refraction in the double quantum dot system

摘要

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.