In a groundbreaking study, a team of researchers from the University of Melbourne and RMIT University in Australia has uncovered a novel photoluminescent color center in a rare form of diamond known as lonsdaleite. This discovery could potentially open new avenues in the energy sector, particularly in quantum technologies and sensing applications.
The researchers, led by Giannis Thalassinos and Andrew D. Greentree from the University of Melbourne, and Dougal G. McCulloch from RMIT University, identified a new defect, dubbed RU1, in lonsdaleite grains found in the ureilite meteorite NWA7983. Their findings were published in the journal Nature Communications.
Lonsdaleite, also known as hexagonal diamond, has been theorized to support optically active point defects, but until now, no such centers had been experimentally observed. The team’s discovery of the RU1 defect marks the first experimental evidence that lonsdaleite can indeed host photoluminescent color centers. These centers exhibit bright and stable emission across a broad spectrum of 550-800 nm, with optimal excitation in the blue range (~455 nm) and a peak emission at ~700 nm.
The researchers employed time-resolved photoluminescence techniques to study the defect’s properties. They found that the RU1 center has an excited-state lifetime of 14 nanoseconds, with no detectable blinking, bleaching, or charge conversion. This stability is crucial for potential applications in quantum technologies, where consistent and reliable performance is essential.
From the excitation-emission energetics, the team inferred an unresolved zero-phonon line near 550 nm. Correlative electron microscopy confirmed the lonsdaleite host lattice, and compositional analysis suggested that nitrogen, silicon, or nickel could be plausible constituents of the RU1 defect.
The practical applications of this discovery for the energy sector are promising. Quantum technologies, such as quantum sensing and quantum communication, could benefit from the unique properties of lonsdaleite color centers. These centers could potentially be used to develop highly sensitive magnetic field sensors, which are valuable in various energy applications, including oil and gas exploration, and power grid monitoring. Additionally, the stable and bright emission of these color centers could be harnessed for advanced imaging and spectroscopy techniques, enhancing our ability to monitor and optimize energy systems.
Moreover, the discovery of hexagonal-diamond color centers opens up a new family of solid-state quantum emitters, which could lead to innovative solutions in energy storage, conversion, and distribution. As research in this area progresses, we may see lonsdaleite-based technologies playing a significant role in the future of the energy industry.
This article is based on research available at arXiv.