Isotopically Purified NV Diamonds for Advanced Quantum Sensing

This study focuses on the fabrication of isotopically purified nitrogen-vacancy (NV) diamonds, which are used for advanced quantum sensing applications. The diamonds are produced using Chemical Vapor Deposition (CVD) techniques and advanced post-growth processing methods, including electron irradiation to create vacancies and high-temperature annealing to activate NV centers. These isotopically purified diamonds exhibit enhanced spin coherence times, which are critical for high-precision quantum sensing and computation.

Key Points:

1. Isotopic Purification and Material Synthesis: The diamonds are synthesized using 99.999% 12C-enriched methane as the source gas, resulting in ultrapure diamond layers. These layers are then doped with nitrogen (15N) during the CVD process to create NV centers.

2. Characterization: Advanced techniques, such as Secondary Ion Mass Spectroscopy (SIMS), are used to measure the isotopic purity and nitrogen content of the diamond layers. The study reports a 99.99% enrichment of 12C and controlled nitrogen doping, which significantly reduces the presence of spin noise from 13C isotopes.

3. Post-Growth Processing: After growth, the diamonds undergo electron irradiation to introduce vacancies, which, in combination with nitrogen impurities, form NV centers. High-temperature annealing at 1000°C further enhances the NV centers' stability and coherence.

4. Spin Properties and Quantum Performance: The NV centers' properties, including Rabi contrast and Hahn echo coherence times, are measured. The study demonstrates spin coherence times of up to 34 µs, which are competitive with literature values.

5. Prototype Quantum Devices: The high-quality NV diamonds are integrated into prototype quantum sensing devices, such as real-time spectrum analyzers, showcasing their potential for precision quantum measurements at room temperature.

6. Applications: These diamonds are not only valuable for quantum sensing but also for quantum computation, where the stability and coherence of qubits are crucial. The research highlights the versatility of these materials in the development of next-generation quantum technologies.

7. Collaboration and Future Prospects: This research is part of the European Union-funded AMADEUS project. The collaboration between Diatope GmbH and its partners is key to advancing the fabrication of engineered diamond materials for quantum technologies.

In conclusion, the development of isotopically purified NV diamonds significantly enhances quantum sensing capabilities, and these advancements open up new possibilities for both sensing and quantum computing applications.