Stark Tuning and Electrical Charge State Control of Single Divacancies in Silicon Carbide

Neutrally charged divacancies in silicon carbide (SiC) which are known as paramagnetic color centers, their long coherence times and near-telecom operating wavelengths. However, local strain inhomogeneity can randomly perturb their optical transition frequencies, which degrades the indistinguishability of photons emitted from separate defects and hinders their coupling to optical cavities. In this study, electric fields can be used to tune the optical transition frequencies of single neutral divacancy defects in 4H-SiC over a range of several GHz via the DC Stark effect. The same technique can also control the charge state of the defect on microsecond timescales. Using fluorescence-based charge state detection, it is demonstrated that both 975 and 1130 nm excitation can prepare their neutral charge state with near unity efficiency