Nonlinear energy transfer in quantum dot and metallic nanorod nanocomposites

Abstract

We have investigated the nonlinear energy transfer in a quantum dot (QD) and metallic nanorod (MNR) nanocomposite. An intense probe laser field is applied to monitor two-photon energy transfer from the QD to the MNR and a control laser field is applied to control the energy transfer rate. Induced dipoles are created in the QD and MNR and these dipoles are interacting with each other. Surface plasmon resonances (SPRs) are also created in the MNR due to a coupling of charge fluctuations and external laser fields. Therefore, there is a dipole–dipole interaction between excitons in the QD and SPRs in the MNR. Due to this interaction, the two-photon energy is transferred from the QD to the MNR. Using the density matrix method, the energy transfer rate between the components of the system is evaluated. It is found that the energy transfer rate has one peak due to the transfer of the two-photon energy from the QD to the MNR when the control field is absent. When the control field is applied, this peak disappears. This means no energy transfer between two components of the nanosystems. However, two new peaks appear in the energy transfer rate at two different energies. It is also found that by varying the intensity of the probe field, one can also control the energy transfer from the QD to the MNR. These are interesting findings of the paper and they can be used to fabricate nanosensors, nanoswitches, and energy transfer devices.