We have developed a theory of the quantum yield for plasmonic nanowaveguide where the cladding layer is made of an ensemble of quantum dots and the core layer consists of an ensemble of metallic nanoparticles. The bound states of the confined probe photons in the plasmonic nanowaveguide are calculated using the transfer matrix method based on the Maxwell equations. It is shown that the number of bound states in the nanowaveguide depends on the dielectric properties of the core and cladding layers. The surface plasmon polaritons (SPPs) produced by the metallic nanoparticles interacts with the excitons of the quantum dots. The radiative and nonradiative linewidths of excitons in the quantum yield are calculated using the quantum mechanical perturbation theory. We have found that the quantum yield decreases as the dipole–dipole interaction between metallic nanoparticles increases. We have also calculated the photoluminescence and found that the enhancement in photoluminescence is due to the SPPs coupling. On the other hand, the quenching in the photoluminescence is due to the quantum yield. We compared our theory with experiments of a nanowaveguide where the core is fabricated from Ag- nanoparticles and the cladding is fabricated from the perovskite quantum dots. A good agreement between theory and experiments is found. Our analytical expressions of the quantum yield and photoluminescence can be used by experimentalists to proforma new types of experiments and for inventing new types of nanosensors and nanoswitches.

A theory of light–matter interaction in plasmonic nanofibers is developed. When probe light propagates inside the nanofiber, it induces surface plasmon polariton (SPPs) and electric dipoles in metallic nanoparticles. The dipoles interact with each other via dipole–dipole interaction (DDI). The energy of photonic bound states in the presence of the SPP and DDI fields are calculated. It has been demonstrated that the number of bound states can be controlled by the strength of SPP and DDI couplings. The spontaneous decay rate for the quantum emitters have been calculated and it is found that decay rate is enhanced when the exciton energy is in resonance with the bound photon energy. Further, it is predicted that the spontaneous decay rate also enhances when the exciton and SPP energies are in resonance. Finally, the photoluminescence in nanofiber is calculated using the density matrix method. The authors' theory is compared with experiments and found a good agreement between theory and experiments. It has been demonstrated that the quenching of the photoluminescence intensity increases as the concentration of the MNPs increases. The findings of the paper can be used to fabricate random lasers and also for inventing new types of nanosensors and nanoswitches.

No abstract