1 Department of Photonics Engineering, Technical University of Denmark2 Risø National Laboratory for Sustainable Energy, Technical University of Denmark
In this thesis we have performed quantum electrodynamics (QED) experiments in photonic crystal (PhC) waveguides and cavity QED in the Anderson localized regime in disordered PhC waveguides. Decay rate measurements of quantum dots embedded in PhC waveguides has been used to map out the variations in the local density of states (LDOS) in PhC waveguides. From decay rate measurements on quantum dot lines temperature tuned in the vicinity of the waveguide band edge, a β-factor for a single quantum dot of more then 85% has been extracted. Finite difference time domain simulations (FDTD) for disordered PhC waveguides have been used to conrm the existence of a densely packed spectrum of strongly conned Anderson localized modes near the waveguide band edge. An one-dimensional disordered model is used to model the statistical properties of Anderson localized modes. As the localization lengths decrease, a simultaneous increase in the average Q-factor and decrease in mode volume is observed, which leads to a large probability of observing strong coupling in disorder PhC waveguides. The effect of losses is shown to reduce the largest Q-factors in the distribution and drastically lower the strong coupling probability. The Q-factor distributions of Anderson localized modes have been measured in PhC waveguides with articial induced disorder with embedded emitters. The largest Q-factors are found in the sample with the smallest amount of disorder. From a comparison with the waveguide model the localization length is shown to increase from 3 − 7 um for no intentional disorder to 25 um for 6% disorder. A distribution of losses is seen to be necessary to explain the measured Q-factor distributions. Finally we have performed a cavity QED experiment between single quantum dots and an Anderson localized mode, where a β-factor of 94% has been measured.