Tunable Optical Resonators with Embedded Diamond Defect
Centres for Quantum Technologies
Defect centres in diamond have shown potential for a wide range of applications in sensing,
metrology and quantum optics. In particular nitrogen and silicon vacancies have been
exploited as nanoscale magnetometers, quantum memories and single photon emitters. The
efficiency of such optical devices is dependent on the light-matter interaction, the effects of
which can be improved by embedding the defect centre in a resonant cavity. The cavity
enhances both the optical field strength on-resonance and the spatial overlap of the optical
mode and defect centre. Improvements in defect centre creation and micro-optic
fabrication have allowed the systematic creation of defect centres within free space and
guided wave resonator structures.
One of the major challenges in the use of optical resonators is in matching the resonant
wavelength of the device with the wavelength of the defect centre embedded in it. Free
space designs have the advantage of being able to modulate the physical cavity length via
mechanical actuators, though there are significant barriers to scaling of these setups for
multi-node systems or compact point of use sensors. On the other hand, although guided
wave resonators present extremely compact device footprints, it has proven extremely
difficult to tune the resonant wavelength of these devices in diamond optical devices.
This project will develop means by which high Q-factor diamond optical resonators can be
tuned to overlap with embedded defect centres. A number of parallel methods will be
explored, including: heterogeneous integration of electro-optical materials, local thermal
tuning of thermally isolated resonator devices and direct electronically doped diamond.
Devices will be realised in-house at the Institute of Photonics in Strathclyde and the student
will undertake design, fabrication and measurement activities.
For further details please contact Dr Michael Strain:
michael.strain@strath.ac.uk