New color centers are being discovered in diamond every year. For the most part these are guided by the desire to replace the silicon-vacancy (SiV) by emitters with higher quantum efficiency and longer storage times. I will discuss color centers produced by some of the most recently implanted elements into diamond including Ge, Sn, Pb, Mg. I will also discuss the rationale for elements to be implanted soon. Finally I will also discuss new options for the future, including designer color centers made possible by novel diamond growth techniques.
New color centers are being discovered in diamond every year. For the most part these are guided by the desire to replace the silicon-vacancy (SiV) by emitters with higher quantum efficiency and longer storage times. I will discuss color centers produced by some of the most recently implanted elements into diamond including Ge, Sn, Pb, Mg. I will also discuss the rationale for elements to be implanted soon. Finally I will also discuss new options for the future, including designer color centers made possible by novel diamond growth techniques.
In recent years there has been substantial progress in solid-state quantum information demonstrations based on diamond. This ranges from room-temperature multi-qubit quantum registers to spin-photon entanglement to loophole-free Bell tests. Most of these demonstrations are done with the nitrogen-vacancy (NV) center. Recently however the silicon-vacancy (SiV) center has shown a much better coupling to photons, owing to the suppression of spectral diffusion. Still more recently the germanium-vacancy (GeV) has shown much higher quantum efficiency the SiV. However there are tradeoffs. In this talk I will review the various options for quantum information devices in diamond. I will also discuss new options for the future, including designer color centers made possible by novel diamond growth techniques.
The performance of diamond color centers for quantum information and sensing depends strongly on the quality of the material. Specifically, ultra-pure, low-strain diamond is preferred. However, in order to create color centers, non-carbon atoms must be incorporated into the lattice either by rapid growth or implantation. Both these techniques cause defects and lattice damage that degrades ultimate performance. To overcome these problems, we show a molecule-seeded growth technique that decouples the doping and growth processes. The result is near-deterministic creation of specific color centers in chemically pure, low-strain diamond. Data showing selective growth of H3 and NV centers will be presented, where the NV is used to verify that the crystals are low-strain. Future application to other color centers like silicon, germanium, and tin vacancies will be discussed. Also the possibility of direct growth of more complex quantum registers.
Progress in controlling diamond synthesis has made it possible to produce very pure crystals and to incorporate and control atomic impurities and carbon vacancies in the crystal lattice. The appropriate impurity-vacancy combinations can give rise to special defects known as color centers, such as the nitrogen-vacancy (NV) or the silicon-vacancy (SiV), which exhibit exceptional quantum properties with spins that are optically addressable. The use of diamond containing color centers has paved the way for the development of innovative quantum technologies, such as very high-resolution magnetometry and quantum information processing. Nevertheless, the development of quantum sensors at the nanometric scale remains one of the most interesting challenges. In this context, the development of a reliable nanoparticle synthesis technique that allows the desired defects to be incorporated and their quantum optical properties to be modulated is crucial. In this seminar, an efficient and recent method to produce diamond nanoparticles containing NV, SiV and germanium-vacancy (GeV) centers is proposed through direct plasma assisted chemical vapour deposition (CVD) growth. This technique allows good control of both nanoparticle growth processes and color centers formation. The optimization of the CVD nanodiamond growth process is presented, showing the impact of different plasma parameters and gas phasecomposition on nanoparticle crystallinity, size and shape. Morphological characterizations reveal the production of small (around 100 nm) and well faceted nanodiamond particles. In addition, the SiV and GeV color centers incorporation can be tuned within this material by varying the gas phase composition which emphasizes the high flexibility of the CVD growth technique. Finally, the quantum properties of the incorporated color centers have been successfully investigated under extreme pressure conditions (up to ~ 180 GPa) showing a monotonic blue shift of their optical zero-phonon line. Since their luminescence remains stable, SiV and GeV centers emerge as high-pressure nanosensors.
The silicon vacancy (SiV) color centers in diamond have significant potential in the fields of quantum information, nanophotonics, bioimaging and sensing, due to its good structural stability at room temperature, strong photostability, short luminescence lifetime, narrow zero-phonon line bandwidth, and avoidance of biological autofluorescence. They have attracted extensive attention and in-depth research from researchers. The applications of SiV color centers in the above areas require addressing key issues such as control over the number and charge state of SiV color centers in diamond, as well as improving the luminous efficiency. Therefore, this review summarizes some recent relevant research progress, including common methods for preparing SiV color centers, control over their luminescence intensity, preparation of SiV single-photon sources, and research on the control of SiV color center charge states. Based on these, an outlook is provided for the preparation and application of SiV color centers in diamond.
Nitrogen-vacancy (NV) color centers in diamond have emerged as a focal point in quantum technology research due to their exceptional optical and electronic spin properties. This discovery not only expands our understanding of the material properties of diamond but also paves the way for practical applications in quantum technology. As a solid-state spin quantum system characterized by long electron spin coherence times and stable performance, NV color centers offer distinct advantages in quantum information processing. Recent advancements have enabled the fabrication of high-quality NV color centers with controllable concentration and spatial positioning through techniques such as in situ doping, ion implantation, and hybrid approaches. These technological breakthroughs have significantly enhanced the efficiency of NV center fabrication, thereby establishing a robust foundation for their widespread application in quantum sensing and quantum information technologies. This review provides a comprehensive introduction to the structure and fundamental properties of NV color centers in diamond, an in-depth analysis of recent progress in their fabrication techniques, and a critical discussion of their current applications in quantum science and technology. Additionally, the challenges, open questions, and future research directions in NV color center studies are addressed.
Silicon-vacancy (SiV) centers in diamond are gaining an increased interest for application, such as in quantum technologies and sensing. Due to the strong luminescence concentrated in its sharp zero-phonon line at room temperature, SiV centers are being investigated as single-photon sources for quantum communication, and also as temperature probes for sensing. Here, we discussed strategies for the fabrication of SiV centers in diamond based on Si-ion implantation followed by thermal activation. SiV color centers in high-quality single crystals have the best optical properties, but polycrystalline micro and nanostructures are interesting for applications in nano-optics. Moreover, we discuss the photoluminescence properties of SiV centers in phosphorous-doped diamond, which are relevant for the creation of electroluminescent devices, and nanophotonics strategies to improve the emission characteristics of the SiV centers. Finally, the optical properties of such centers at room and high temperatures show the robustness of the center and give perspectives for temperature-sensing applications.