Wide-range electrical tunability of single-photon emission from chromium-based colour centres in diamond

We demonstrate electrical control of the single-photon emission spectrum from chromium-based colour centres implanted in monolithic diamond. Under an external electric field, the tunability range is typically three orders of magnitude larger than the radiative linewidth and at least one order of magnitude larger than the observed linewidth. The electric and magnetic field dependence of luminescence gives indications of the inherent symmetry, and we propose Cr-X or X-Cr-Y-type non-centrosymmetric atomic configurations as the most probable candidates for these centres.