Efficient Photonic Integration of Diamond Color Centers and Thin-Film Lithium Niobate

• Main Authors: Riedel, Daniel, Lee, Hope, Herrmann, Jason F, Grzesik, Jakob, Ansari, Vahid, Borit, Jean-Michel, Stokowski, Hubert S, Aghaeimeibodi, Shahriar, Lu, Haiyu, McQuade, Patrick J, Melosh, Nick A, Shen, Zhi-Xun, Safavi-Naeini, Amir H, Vučković, Jelena
• Format: Journal Article
• Language: English
• Published: 27.06.2023
• Subjects: Physics - Applied Physics; Physics - Optics; Physics - Quantum Physics
• DOI: 10.48550/arxiv.2306.15207

On-chip photonic quantum circuits with integrated quantum memories have the potential to radically progress hardware for quantum information processing. In particular, negatively charged group-IV color centers in diamond are promising candidates for quantum memories, as they combine long storage times with excellent optical emission properties and an optically-addressable spin state. However, as a material, diamond lacks many functionalities needed to realize scalable quantum systems. Thin-film lithium niobate (TFLN), in contrast, offers a number of useful photonic nonlinearities, including the electro-optic effect, piezoelectricity, and capabilities for periodically-poled quasi-phase matching. Here, we present highly efficient heterogeneous integration of diamond nanobeams containing negatively charged silicon-vacancy (SiV) centers with TFLN waveguides. We observe greater than 90\% transmission efficiency between the diamond nanobeam and TFLN waveguide on average across multiple measurements. By comparing saturation signal levels between confocal and integrated collection, we determine a $10$-fold increase in photon counts channeled into TFLN waveguides versus that into out-of-plane collection channels. Our results constitute a key step for creating scalable integrated quantum photonic circuits that leverage the advantages of both diamond and TFLN materials.