A Diamond Nano-Electro-Mechanical System for Frequency Tuning and Stabilization of Diamond Tin-Vacancy Centers

Distributing entanglement via future quantum networks will enable applications such as large-scale distributed quantum computing and secure communication. The Tin-Vacancy (SnV) color center in diamond is a promising candidate as next-generation quantum network node, due to its good optical coherence, spin control, and compatibility with nanophotonic integration. Towards the goal to distribute entanglement between remote SnVs via optical links, we require indistinguishable coherent photon emission of remote SnVs. However, tuning the emission frequency of SnVs with electric fields is limited in range by the center's inversion symmetry. Here, we report on a diamond-based Nano-Electro-Mechanical System (NEMS) for frequency tuning of SnVs via strain tuning, tackling both the challenge of tuning remote SnVs to the same frequency and that of actively stabilizing emission frequencies against spectral diffusion. By varying the applied bias voltage to the diamond NEMS, we show control over the local strain environment and shift the resonant optical frequencies of the SnVs over a large range, comparable to the inhomogeneous frequency distribution. Finally, we utilize the frequency tunability to stabilize the emission frequency of a SnV via a real-time gate modulation feedback scheme for over 7 hours, reducing its frequency wandering over 45-fold.