This paper demonstrates one- and two-dimensional photonic crystal (PhC) cavities fabricated in thin-film diamonds, achieving quality factors (Q) of 1.8 × 10⁵ and 1.6 × 10⁵ respectively—the highest Qs for visible PhC cavities in any material. The simple, high-yield fabrication process, based on conventional planar techniques, contrasts with previous complex methods. Fiber-coupled 1D PhC cavities show high photon extraction efficiency, and optical coupling between a single SiV center and a cavity at 4 K achieves a Purcell factor of 18. This platform significantly improves quantum node performance and scalability.

Sophie W. Ding, Michael Haas, Xinghan Guo, Kazuhiro Kuruma, Chang Jin, Zixi Li, David D. Awschalom, Nazar Delegan, F. Joseph Heremans, Alexander A. High, Marko Loncar