A super coupling of radiation field and excitons confined in spatially periodic structure

By means of the microscopic nonlocal response theory, we analyze the mode structure of the coupled system of radiation and periodically confined excitons in multiple thin films. It is clarified how the spatially separated excitons which are coupled with each other via radiation share the radiative shift and width depending on the period and thickness of the excitonic active layers, and on their quantum number of confined levels. These results show the possibility that the very large radiative width can be realized by setting up the period and thickness of the excitonic active layers at appropriate values, which leads to very fast radiative decay beyond the saturated value of the giant oscillator strength effect.