Quantum dot photonic crystal circuits

The first solid state structures for cavity quantum electrodynamic studies were realized analog to established designs from the field of trapped atom or ions: Single emitters (e.g. semiconductor quantum dots) were place in optical resonators with small mode volumes and a large quality factors. These devices have allowed the demonstration of effects that were already observed for atom/ion systems, like the strong coupling of a single emitter to an optical cavity mode [1,2]. However, a solid state platform offers much more control over the optical density of states than the open resonators used in quantum optics experiments with atoms or ions. Modern nano-fabrication tools can be used to pattern the dielectric environment of the emitters with nanometer precision, opening completely new possibility to tailor their photonic environment. This has led to the development of alternative structures, e.g. for single photon sources. Cavity based single photon sources rely on the Purcell effect to direct the spontaneous emission into a defined optical mode. However, it is also possible to collect a large fraction of the emitted photons in a single mode when the emission into other modes is suppressed. This can be achieved by embedding the quantum dots in photonic crystal waveguides [3] or nanowires [4]. A big advantage of these structures is their broadband operation that is not limited by the bandwidth of a cavity resonance.