Single Crystal Diamond Membrane for Quantum Technologies

Optically active spin defects in diamond, often named color centers, are prime candidates for quantumtechnologies, including quantum networking, computing, sensing, and photonics. Integrating single-crystal diamond with heterogeneous materials unlocks numerous research directions that are non-trivial for bulk diamond or nanodiamond. This thesis describes a deterministic method for diamond membrane synthesis and integration to expand integration options for hosted color centers. This heterogeneous material platform enables efficient spin-photon interfaces and improves the coherence of color centers, two key elements of quantum networking. The platform also offers a versatile and practical interface for quantum sensing and provides an opportunity to explore atomic-scale optical interaction in solids. Chapter 1 introduces the fundamentals of quantum technology, diamond color centers for quantum applications, and material properties of diamond with synthesis methods. Chapter 2 provides the research background of low-dimensional diamond fabrication and details our approaches to generating high-quality diamond films and integrating them with a wide selection of materials. Chapter 3 demonstrates multiple fabrication methods of nanophotonic cavities with diamond-based heterostructures and their coupling to color centers. Chapter 4 presents our work on strain generation in thin-film diamonds and modification of the spin dynamics for tin-vacancy centers using strain. Chapter 5 discusses the spin coherence of nitrogen-vacancy centers in diamond membranes and their applications for quantum bio-sensing. Chapter 6 describes our study on near-field enhancement of germanium-vacancy centers based on the behavior of nearby carbon vacancies. Chapter 7 concludes the thesis and provides an outlook on this platform in quantum technologies.