Optical interfacing of tin-vacancy spin qubits in diamond

Abstract

Color centers in diamond, specifically the group-IV-vacancy centers, have emerged as promising candidates among solid state qubits. Among these, the tin-vacancy (SnV) center features the optimum combination of long spin coherence time and favorable optical properties. We here investigate the generation of indistinguishable single photons from SnV centers and explore the influence of residual spectral diffusion. To improve the photon collection efficiency we fabricate a planar optical antenna based on two silver mirrors coated on a thin (sub-µm) single crystal diamond membrane. We demonstrate its operation at room and cryogenic temperatures and strong enhancement of the collectible photon rate.