Network interfaces for diamond spin qubits

This project will address the challenge of fabricating devices which facilitate efficient coupling of a diamond colour centre to an optical network, as a component of scalable chips for quantum computing or quantum communications. It builds on recent advances by the group in the controlled writing of colour centre qubits into diamond using laser processing, and on extensive experience within the group in the fabrication of precision optical microcavities using focused ion beam milling.

The overall goal will be to fabricate monolithic Fabry Perot microcavity structures in diamond membranes which can be tuned into resonance with the zero phonon line of a nitrogen vacancy defect in diamond to provide an enhanced coupling and an efficient quantum interface when cooled to 4K. Callenges are in the fabrication process and in identifying and implementing a suitable tuning mechanism.

The first year of the project will be dedicated to initial fabrication and characterisation of diamond cavities and some preliminary research of tuning mechanisms. A number of possible mechanisms are already being discussed so the student will carry out some literature research and we will hold discussions with relevant external experts where necessary. At the end of the first year we will have identified the most promising tuning mechanism to pursue and will have demonstrated the first cavity devices.

The second year will then be spent implementing one or more tuning mechanisms to test their effectiveness. In the third year focus will be on tuning into resonance with implanted NV centres and measuring the properties of the spin-photon interface.
The student will benefit from a well-equipped optics lab and be part of a wider team working on different aspects of diamond quantum processors, including a senior postdoc who will provide some day-to-day guidance. The group has recent purchased a closed-cycle cryostation which will allow rapid characterisation and will be accessible to the student to use. The student will also benefit from links with the UK Hub in Quantum Computing and Simulation of which the group is part, and from collaborations with the University of Warwick and industrial partners.

The project focuses primarily on the EPSRC theme of quantum technologies.