NV Centers in Diamonds
We are using ensembles of many NV centers to detect the tiny magnetic fields of nuclear spins. These fields can either be static or dynamic, but the static fields created by nuclear spins is so small that it is nearly impossible to detect, except in special cases. Nuclear spins, however, create time-varying AC fields at well-defined frequencies. NV centers can detect these AC fields through the use of sophisticated sequences of microwave pulses applied to manipulate the NV spin orientation. We are adapting these techniques to detect nuclear spins optically (ODNMR) under high pressures. This approach will enable new measurements at pressures that have never been explored previously.
What are NV Centers?
Diamonds contain various types of impurities, many of which give them different types of colors and hues. One particular defect, the negatively-charged Nitrogen-Vacancy site, is particularly important for quantum technologies. An NV center consists of a site where one of the carbon atoms of the diamond lattice is replaced by a nitrogen, and adjacent to this nitrogen is a vacancy. As for any color center in a semiconductor, electrons can be bound to such a site, with a particular series of energy levels that live within the bandgap of the host lattice.
The electrons can be excited optically, and fluoresce with a particular wavelength. Importantly, the spin state of NV centers is S=1 and the intensity of the emitted fluorescence light depends on the orientation of the spin state.
Quantum Information Technology
It is possible to detect the optical signature of a single NV center, which can then be used as a qubit for possible quantum technology applications. One of the great advantages of NV centers is that they can be initialized to the ground state via optical pumping, and microwaves can be then be used to create any possible quantum state.
A single NV center/qubit can be manipulated locally, but can be entangled with a distant NV center through the emission and absorption of a photon. Importantly, NV centers have long decoherence times, depending on the temperature and isotopic makeup of the diamond lattice. The spin of the NV center gives it a net magnetic moment that can interact with a magnetic field through the Zeeman effect, and hence NV centers can be used for sensitive magnetometry.
Recent Publications
ac Sensing Using Nitrogen-Vacancy Centers in a Diamond Anvil Cell up to 6 GPa Journal Article
In: Phys. Rev. Applied, vol. 16, no. 5, pp. 054014, 2021.
Chapter Eight - Optically detected NMR in a diamond-anvil cell for geochemistry Book Section
In: Hubbard, Colin D.; Eldik, Rudi (Ed.): Advances in Inorganic Chemistry, vol. 78, pp. 269–287, Academic Press, 2021, ISSN: 0898-8838.
Novel color center platforms enabling fundamental scientific discovery Journal Article
In: InfoMat, vol. 2, pp. 1–22, 2020.
The promise of optical NMR spectroscopy for experimental aqueous geochemistry Journal Article
In: Am. J. Sci., vol. 320, pp. 533–545, 2020.
Optically detected magnetic resonance of nitrogen vacancies in a diamond anvil cell using designer diamond anvils Journal Article
In: Appl. Phys. Lett., vol. 111, no. 22, pp. 221903, 2017.