Quantum optical study of quality factor and energy level splitting for a quantum dot within optical cavity

A nanosystem containing a quantum dot within an optical cavity is a platform for the study of important quantum phenomena such as photon antibunching, entanglement, single photon generation, and quantum information. The use of such a system in these technologies depends on achieving a strong coupling mode between the quantum dot and the optical cavity. In this study, using a quantum optical approach, the energy Eigen values of a system including a quantum dot within an optical cavity were calculated. Then, for different quantum dots and optical cavities, the threshold conditions were studied to achieve strong coupling mode. The results showed that with increasing the coupling constant, the energy levels splitting increases and the threshold conditions are more favorable for achieving strong coupling mode. The energy level splitting threshold for the quantum dot with a decay rate of 2 μeV within optical cavities with a decay rate of 45 to 205 μeV occurred at a coupling constant of 10.75 to 50.75 μeV. In fact, it was observed that in order to achieve a strong coupling mode in such systems, it is necessary to go to the engineering of cavities with lower decay rates because the change in quantum dots does not have a significant effect on achieving this goal. Also, in a system with such a quantum dot, which has a coupling constant of 35 μeV within an optical cavity with energies of 20 to 140 μeV, the quality factor is in the range of 4930 to 5060.