A Diamond-Photonics Platform Based on Silicon-Vacancy Centers in a Single Crystal Diamond Membrane and a Fiber-Cavity

We realize a potential platform for an efficient spin-photon interface, namely negatively-charged silicon-vacancy centers in a diamond membrane coupled to the mode of a fully-tunable, fiber-based, optical resonator. We demonstrate that introducing the thin $sim 200 nm$, single crystal diamond membrane into the mode of the resonator does not change the cavity properties, which is one of the crucial points for an efficient spin-photon interface. In particular, we observe constantly high Finesse values of up to 3000 and a linear dispersion in the presence of the membrane. We observe cavity-coupled fluorescence froman ensemble of SiV^- centers with an enhancement factor of sim 1.9. Furthermore from our investigations we extract the ensemble absorption and extrapolate an absorption cross section of \(2.9 pm 2\) cdot 10^-12 cm² for a single SiV^- center, much higher than previously reported.