  The recent maturation of hybrid quantum devices has led to significant
enhancements in the functionality of a wide variety of quantum systems. In
particular, harnessing mechanical resonators for manipulation and control has
expanded the use of two-level systems in quantum information science and
quantum sensing. In this letter, we report on a monolithic hybrid quantum
device in which strain fields associated with resonant vibrations of a diamond
cantilever dynamically control the optical transitions of a single
nitrogen-vacancy (NV) defect center in diamond. We quantitatively characterize
the strain coupling to the orbital states of the NV center, and with mechanical
driving, we observe NV-strain couplings exceeding 10 GHz. Furthermore, we use
this strain-mediated coupling to match the frequency and polarization
dependence of the zero-phonon lines of two spatially separated and initially
distinguishable NV centers. The experiments demonstrated here mark an important
step toward engineering a quantum device capable of realizing and probing the
dynamics of non-classical states of mechanical resonators, spin-systems, and
photons.
