Superluminal propagation of light is a well-established phenomenon and has motivated immense research interest that has led to state-of-the-art knowledge and potential applications in the emerging technology of quantum optics and photonics. This study presents a theoretical analysis of the gain-assisted superluminal light propagation in a four-level
N-type atomic system by exploiting the scheme of electromagnetically induced gain and superluminal propagation of surface plasmon polaritons (SPPs) along the gain-assisted atomic-metal interface simultaneously. In addition, a theoretical demonstration is presented on the comparison between Fresnel's rotary photon drag and SPP drag in view of light polarization state rotation by rotating the coherent atomic medium and the atomic-metal interface, respectively. Analogous to photon drag in the superluminal anomalous dispersion region where light polarization rotation occurs opposite the rotation of the gain-assisted atomic medium, the rotation of the atomic-metal interface also rotates the polarization state of SPPs opposite the rotation of the interface. This further confirms the superluminal nature of SPPs propagating along the interface with negative group velocity. Rabi frequencies of the control and pump fields considerably modify both photon and SPP drag coefficients. Metal conductivity also controls SPP propagation.
In this study, we designed a plasmonic system containing an array of nanoparticles (NPs) coupled to a quantum dot (QD) to generate entangled photons. The interaction of incoming light with the array of NPs generates a modified plasmon resonance, so-called lattice-plasmon (interaction of the NPs near-field with the photonic mode). Due to its unique optical properties, the lattice-plasmon strongly manipulates the output modes’ entanglement behavior. This is mainly because of the influence of the lattice-plasmon on the transition and dephasing rates of the quantum dot. It is shown that it can be possible to manipulate the QD decay rates via the optical properties of the lattice-plasmon. Also, to manage the output modes entanglement, the emphasis is put on the retarded field effect, which dramatically impacts the lattice-plasmon optical properties. It is theoretically found that engineering the optical properties of the lattice-plasmon facilitates the manipulation of the entanglement behavior.