Optical engineering of colour centres in diamond

Thesis

Ultrafast laser fabrication of NV− centres has been shown to produce highly coher- ent NV− centres within diamond with high fabrication accuracy, expanding the applicability of the defect within quantum technologies. However this technique is yield limited due to a required thermal annealing step. Within, this thesis presents the first, near-unity yield, fabrication of single NV− centres in commerically available high purity diamond using a homebuilt ultrafast fabrication system. Thermal annealing is replaced by a low energy ultrafast pulse train which allows for NV− generation to be monitored using confocal fluorescence microscopy. Each fabrication site showed a g(2)(0) < 0.5, demonstrating singularity. The fabrication precision has been calculated to be isotropically ∼250 nm, suggesting that nitrogen concentration is the limiting factor. This thesis details the construction and operating principles of the homebuilt fabrication system, which includes the use of adaptive optic elements. Additionally this thesis investigates phenomena observed during ultrafast farbication of NV− centres using ab initio calculations of defect interactions within diamond. These simulations suggest that hybridisation may be responsible for transient effects seen during fabrication. In addition, these simulations demonstrate that the ultrafast laser fabrication of defects may provide an invaluable window into defect formation and fabrication in the solid state.

Authors: Kirkpatrick, A

• DOI: 10.5287/ora-2nayookbd
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: NV centre; laser fabrication; colour centres; defects; diamond
• Subjects: Quantum computing; Optics