In the realm of energy and quantum technologies, diamonds are gaining significant attention due to their exceptional properties. A team of researchers, including Francesco Mazzocchi, Martin Neidig, Hideaki Yamada, Sebastian Kempf, Dirk Strauss, and Theo Scherer, from various institutions, has been exploring the potential of diamonds in these fields. Their recent study, published in the journal Physical Review Applied, focuses on understanding and mitigating losses in diamond materials, which is crucial for their application in quantum technologies and high-power systems like nuclear fusion reactors.
Diamonds, particularly those with engineered nitrogen-vacancy (NV) centers, are highly sensitive platforms for quantum sensing. They are also used as high-optical-quality windows in Electron Cyclotron Resonance Heating (ECRH) systems within nuclear fusion reactors. However, a significant challenge lies in developing ultra-low-loss, high-optical-quality single-crystal diamond substrates that can meet the growing demands for quantum coherence and power handling.
Traditionally, researchers have used Fabry-Perot microwave resonators to evaluate dielectric losses in diamonds. These devices compare the resonance quality factors of the cavity with and without the sample. However, these resonators have limitations in resolution, typically around 10^-5, due to the need to keep the resonator dimensions within a reasonable range.
In contrast, the researchers in this study utilized superconducting thin-film micro-strip resonators, which offer Q factors exceeding 10^6, providing higher sensitivity for assessing ultra-low-loss materials. They examined four diamond samples grown through different processes, analyzing their dielectric losses at extreme low temperatures (sub-Kelvin) within the Two-Level System (TLS) framework.
Complementary Raman spectroscopy measurements allowed the researchers to associate higher nitrogen content with increased losses. Moreover, they investigated how different growth processes influence the incorporation of these defects into the crystal lattice. This understanding is crucial for optimizing the growth processes to minimize losses and enhance the performance of diamond materials in various applications.
The findings of this study contribute to the ongoing efforts to develop advanced materials for quantum technologies and high-power systems. By understanding and mitigating losses in diamond materials, researchers can pave the way for more efficient and powerful quantum sensors and more robust components for nuclear fusion reactors. This research was published in the journal Physical Review Applied.
This article is based on research available at arXiv.