Microscopic study of optically-stable, coherent color centers in diamond generated by high-temperature annealing

TL;DR

This study introduces a high-temperature annealing method to produce high-quality, stable nitrogen vacancy centers in diamond, enhancing their quantum properties and environmental stability for quantum technology applications.

Contribution

The paper presents a novel high-temperature annealing technique for creating and optimizing NV centers in diamonds without damage, improving their quantum coherence and environmental stability.

Findings

Nearly all NV centers had stable, Fourier-transform-limited spectra.

HTA reduces noise sources and triples decoherence time.

Vacancy activation explains spin bath reconfiguration.

Abstract

Single color centers in solid have emerged as promising physical platforms for quantum information science. Creating these centers with excellent quantum properties is a key foundation for further technological developments. In particular, the microscopic understanding of the spin bath environments is the key to engineer color centers for quantum control. In this work, we propose and demonstrate a distinct high-temperature annealing (HTA) approach for creating high-quality nitrogen vacancy (NV) centers in implantation-free diamonds. Simultaneously using the created NV centers as probes for their local environment we verify that no damage was microscopically induced by the HTA. Nearly all single NV centers created in ultra-low-nitrogen-concentration membranes possess stable and Fourier-transform-limited optical spectra. Furthermore, HTA strongly reduces noise sources naturally grown in ensemble samples, and leads to more than three-fold improvements of decoherence time and sensitivity. We also verify that the vacancy activation and defect reformation, especially H3 and P1 centers, can explain the reconfiguration between spin baths and color centers. This novel approach will become a powerful tool in vacancy-based quantum technology.