Towards scalable and efficient single photon sources

Abstract

This thesis investigates the development of techniques to enable the creation of brighter and easier to scale single photon emitters. This is possible with the use of a novel nanoantenna design paired with a redesigned confocal microscope capable of addressing multiple sources in parallel. The nanoantenna design is based on a hemishperical cavity which is typically used in the design of lasers. These are the source of their very high directivity. The design is adapted to allow its integration with solid state sources such as quantum dots and defect centres in diamond. By modifying the properties of the mirror enclosing the cavity it is possible to precisely control the quality factor and the Purcell enhancement of the emission. Additionally, due to its monolithic nature the design is highly stable and permits the incorporation of additional contacting layers to tune the emitters. The new microscope design makes use of multicore fibres on its excitation and collection arms in order to have multiple independent focii on the sample. The design is demonstrated on a nanowire sample were two single photon streams from two separate nanowires are collected simultaneously. The new design also makes use of a quasi-4F lens configuration to minimize beam displacement and optical aberrations. Finally, a new open source tool is developed to facilitate the analysis of time correlated single photon experiments. All the algorithms are optimized to make adequate use of modern computer’s memory hierarchy and multicore nature.