Diamond is a wide bandgap (and thus transparent across many wavelengths) material that hosts optically active color centers. We can use the spin levels of one of these color centers to define a qubit which can store or process quantum information. Of the many color centers which can be found in diamond, our group primarily works on the negatively charged silicon vacancy (SiV) center. The SiV is bright and stable and has coherent ground-state spin levels, and what’s more, its orbital levels couple very strongly to mechanical strain in the diamond lattice. This means we can use strain to tune an SiV’s optical frequency, or alternatively to coherently drive its spin levels. Our research focuses on expanding the applications of these spin-mechanical interactions and on probing the physics of mechanical (phononic) excitations in the quantum regime, for example the possibilities of using phonons as carriers of quantum information.

[Young-Ik Sohn, et al. Nature Communications 9. 2012 (2018)]