Optically detected NMR in a diamond-anvil cell for geochemistry

Developments in quantum-information processing are being adapted to perform nuclear-magnetic resonance (NMR) measurements on solutions in very small volumes. Here we describe efforts to adapt the technology to a diamond-anvil cell (DAC), with the goal of conducting solution NMR measurements at elevated pressures and temperatures. At the center of the method is the use of diamonds that have a particular type of defect that pairs a nitrogen atom substitution for near-surface carbon with a vacancy. These NV- sites have unpaired electrons that can be excited while conserving electron spins and the amount of light released upon decay of the excited state depends upon the orientation of the electron spin. Under certain conditions the NV- centers can probe AC magnetic fields from nearby nuclei with exquisite sensitivity.