Quantum localization of light and non-Markovian photoemission process in photonic crystals

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Artificial crystals with a large periodic modulation of their refractive indices, which are called photonic crystals, can realize photonic bandgaps, or frequency ranges in which there is no radiative eigenmode. Those atoms/molecules whose optical transition is close to the frequency of the photonic bandgaps are expected to bring about quantum localization of photons and the relevant non-Markovian photoemission phenomena due to the quantum-electrodynamical effects. In this study, we aimed at the demonstration of these novel quantum-electrodynamical effects by making use of superradiance of rare earth atoms and dye molecules. We developed a code for computation without the slowly-varying-envelope (SVE) approximation for photonic crystals with a large photonic bandgap to which the conventional analysis of based on the finite-difference time-domain method and the SVE approximation is not applicable. We found that the superradiant emission is propagated to the same direction as the excitation laser beam in the case of the pencil-like excitation, and hence, it is the one-dimensional photonic bandgap and photon density of states that are relevant to the behavior of the non-Markovian superradiance even for two- and three-dimensional photonic crystals We examined the superradiance of chelates of rare earth ions With a pulsed dye laser and a streak camera. We also examined the possibility of quantum dots cooled down to an extremely low temperature as an emitter and the usage of the extraordinary photon density of states due to the localized modes of the photonic crystals. On this research process, we obtained successful results such as the lasing of GaAs quantum dots, the first-principle calculation of the vacuum Rabi splitting by coupled bispheres, accurate evaluation of the spectral width of emission bands of single quantum dots by a Mickelson interferometer, calculation of electronic levels of quantum double rings, and their photoluminescence measurements.