High quality factor single crystal diamond mechanical resonators provide a controlled platform for introducing strain to native NV centers. An optimized resonator geometry allows the NV’s electronic spin to coherently couple to the spatially extended phonon modes of the resonator through lattice strain. This coupling can be used for long-range spin-spin interactions and quantum optomechanical control of the resonator.
We are building a novel tool based on single spins in diamond that promises magnetic sensing with nm-scale spatial resolution and sensitivity to single electron spins. Ultimately we hope to reach the sensitivity required to image single nuclear spins, a feat that could lead to nanoscale magnetic resonance imaging of biological systems. In addition to excellent sensitivity and spatial resolution, NV centers are attractive magnetometers due to their minimal back action (the sensor itself is only a single spin!), simple optical readout, and operation over a wide range of temperatures, from room temperature down to liquid helium temperatures.
We use chemical vapor deposition (CVD) at UCSB to grow high quality single-crystal diamond films for nitrogen-vacancy (NV) center magnetometry and related projects involving NV centers. In the CVD process we have incorporated process steps where the diamond is doped with nitrogen gas to gently create a few nanometer-thick diamond layer where NV centers can be formed. Having NVs within nanometers of the diamond surface is critical if they are to be used to sense weak magnetic fields from systems external to the diamond, such as single electronic and nuclear spins, because the spin-spin coupling falls off rapidly with distance.
Nitrogen-vacancy (NV) centers are of great interest for quantum computation and information applications. Coupling NV spins to photons in a photonic cavity is a first step toward integrating NV centers into a scalable quantum network. We are pursuing different approaches to interface NV centers with photons using photonic crystal cavities.