Figure 1. Spectrum and Electronic Structure of the SiV⁻.

(a) Electronic level scheme of the SiV⁻ at zero magnetic field consisting of an orbitally split but spin degenerate ground and excited state doublet. Large level splittings of 48 GHz in the ground and 259 GHz in the excited state, mainly caused by spin orbit coupling, are characteristic for the SiV⁻ and render the system ideal for manipulation using broadband laser pulses. (b) Photoluminescence spectrum of the four zero phonon line transitions of the SiV⁻ centre used throughout this study. The spectrum is obtained under non-resonant excitation at λ_ex=690 nm and at 4 K. The values of the spectral splitting between transitions A and B as well as A and C increase for higher crystal strain and, in this case, indicate an unstrained centre.