SnV centers in nanophotonic diamond devices for quantum networks, Part II- all-optical characterization of the qubit

Future quantum networks able to share entanglement between distant nodes will enable novel applications such as intrinsic secured communication and distributed quantum communication. Color centers in diamond are promising node candidates for such a quantum network, due to their good optical and spin properties. In order to realize large-scale metropolitan quantum networks that can generate entanglement with high fidelity, excellent spin-photon interfaces are required. The tin-vacancy (SnV) center has a relatively large emission fraction of coherent photons and is in first order insensitive to charge noise and thus compatible with nanophotonic integrated devices. Moreover, it may be operated at relatively high temperatures above 1K.



We strive to realize an efficient spin-photon interface using SnV centers in diamond, with the goal of embedding them in nanophotonic structures and employing them as quantum network nodes. N. Codreanu reports in part I on the fabrication and characterization of diamond suspended nanophotonic structures. Here we share the fabrication results of SnV centers embedded in diamond nanopillars for collection efficiency enhancement. In addition, we report on our most recent all-optical measurements of SnV centers on the road towards large-scale on-chip integration.