Building quantum network nodes based on neutral silicon vacancy centers in diamond

Abstract

Color centers in diamond are attractive candidates for implementing single-atom quantum memories in a quantum network. This thesis describes an approach to build quantum networks nodes based on color centers in diamond. We propose to use a novel single-atom quantum memory, the neutral charge state of silicon vacancy (SiV$^0$), as the building block for future quantum network. The unique combination of long spin coherence times and efficient optical transitions makes SiV$^0$ a promising candidate for such application. Leveraging the excellent spin and optical properties of SiV$^0$, we design a hybrid III-V diamond photonic platform that can both enhance the photon emission of SiV$^0$ and perform on-chip frequency conversion to the telecommunication C-band. As a first step towards building quantum network nodes based on SiV$^0$, we design, fabricate and characterize nanophotonic cavities on the GaAs-on-diamond platform. Preliminary results show that a quality factor of 1,328 can be achieved despite the challenges in fabrication. Coupling the cavity to a single SiV$^0$ center in diamond could in principle enable a Purcell enhancement of the SiV$^0$ emission with a factor of 64. This could potentially enhance spin readout and spin-photon entanglement fidelity for SiV$^0$. Eventually, the results and techniques described in this thesis could contribute to the developments of multi-node quantum networks that span across the globe.