Sensing ions in fluids using nanodiamond trapped in a microcavity

Nitrogen-vacancy (NV) colour centres in diamond are rapidly becoming a powerful tool for biosensing, offering coherent and long-lived spin states that can be used to detect electric and magnetic fields with high sensitivity and at nanometre length scales. A particular example of interest is the detection of free radicals in a fluid using a nanodiamond probe, whereby the motion of the charged molecules at the nanodiamond surface reduces the spin relaxation time of the NV centres and affects the measured fluorescence intensity. This project aims to develop a sensor instrument in which nanodiamonds are trapped in optical microcavities and fluorescence measured as a probe of the local environment. Experiments measuring pH, triplet oxygen and metal ions in water will be explored.

The project will be carried out in close communication with Oxford HighQ Ltd, a new spin-out from the group which is developing commercial instrumentation for fluid-based nanoparticle analysis and chemical sensing.