Speaker
Description
Quantum networks play an important role in quantum information science as they promise secure communication as well as applications in distributed quantum computing and quantum metrology. To expand them over large distances, however, quantum repeaters based on entanglement distribution are required to minimize optical fiber losses. This increases the demand for efficient interfaces between photonic and stationary qubits as a source of entanglement. The negatively charged Tin-Vacancy color center in diamond (SnV$^{-}$) is a promising candidate, as it offers Fourier-limited single photon emission and an optically accessible electron spin with millisecond coherence times [1].
To create a quantum repeater segment by entanglement swapping between two spin-photon interfaces, photonic Bell-State measurements are employed. These require a high indistinguishability of the single photon emission from the SnV$^{-}$, which has not yet reached sufficiently high regimes [2].
Here, we demonstrate a high indistinguishability of consecutively emitted photons from a SnV$^{-}$ hosted by an $^{12}\text{C}$ enriched diamond. By observing a raw Hong-Ou-Mandel Visibility of $V_{\text{HOM}}^{\text{raw}}=0.950^{+0.006}_{-0.008}$ and compensating for technical imperfections, an intrinsic indistinguishability up to $0.999$ highlights the SnV's suitability for quantum network applications.
Further work aims to implement fast gate operations by investigating possibilities and limitations of all-optical coherent control of the SnV$^{-}$'s electron spin. Combination of its photonic properties with coherent spin control thus contributes to the development of an efficient source of spin-photon entanglement.
$[1]$ I. Karapatzakis et al., Phys. Rev. X 14, 031036
$[2]$ J. A. Martínez et al., Phys. Rev. Lett. 129, 173603