We study theoretically the dipole-dipole interaction and energy transfer in a hybrid system consisting of a quantum dot and graphene nanodisk embedded in a nonlinear photonic crystal. In our model, a probe laser field is applied to measure the energy transfer between the quantum dot and graphene nanodisk, while a control field manipulates the energy transfer process. These fields create excitons in the quantum dot and surface plasmon polaritons in the graphene nanodisk which interact via the dipole-dipole interaction. Here, the nonlinear photonic crystal acts as a tunable photonic reservoir for the quantum dot, and is used to control the energy transfer. We have found that the spectrum of power absorption in the quantum dot has two peaks due to the creation of two dressed excitons in the presence of the dipole-dipole interaction. The energy transfer rate spectrum of the graphene nanodisk also has two peaks due to the absorption of these two dressed excitons. Additionally, energy transfer between the quantum dot and the graphene nanodisk can be switched on and off by applying a pump laser to the photonic crystal or by adjusting the strength of the dipole-dipole interaction. We show that the intensity and frequencies of the peaks in the energy transfer rate spectra can be modified by changing the number of graphene monolayers in the nanodisk or the separation between the quantum dot and graphene. Our results agree with existing experiments on a qualitative basis. The principle of our system can be employed to fabricate nanobiosensors, optical nanoswitches, and energy transfer devices.

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We study the optical response of a coupled asymmetric semiconductor quantum dot-spherical metal nanoparticle structure. The asymmetric quantum dot has permanent electric dipole moments that also interact with light. We derive the density matrix equations for the system including the modification of the electric field and the exciton-plasmon coupling. We emphasize on the effects of the nonlinear optical rectification and controlled optical bistability and analyze these phenomena for different values of the light intensity and different distances between the quantum dot and the metal nanoparticle. We show that when the system is set in a situation where optical bistability can be produced, the optical rectification of the hybrid system is bivalued. We also analyze the slow-down to reach the steady state when the system is driven close and far from the turning points.

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