Observation of Purcell enhanced emission from diamond defect centers coupled to photonic crystal slow light waveguides

The development of efficient nanophotonic platforms with solid-state defects is an important task for realizing scalable quantum networks. To achieve this, optical cavities with high Q factors and small mode volumes are widely used to boost the performance of the defect centers through their stronger emitter-cavity couplings. This approach, however, can impose strict requirements on the overlap between the optical cavity modes and the defect centers in both spatial and frequency domains. In this work, we alleviate this issue by developing photonic crystal slow light waveguides that allow for broadband optical couplings with Silicon vacancy (SiV) centers in diamond. We fabricate fully suspended 2-dimensional photonic crystal waveguides on a thin film diamond membrane bonded on insulator. Owing to the slow light effect, we observe Purcell enhanced emissions from SiV centers positioned in the waveguides. Our experiment demonstrates a novel way to realize efficient spin-photon interfaces based on defect centers in diamond.