Quantum information technology (QIT), a key frontier field emphasized in China’s “14th Five-Year Plan” and the 2035 long-term development goals, serves as a core driver for leading the new round of scientific and technological revolution and industrial transformation. Its in-depth development is of great significance for enhancing national technological competitiveness, promoting innovation-driven development, and breaking through bottlenecks in traditional information technologies. As a critical material foundation for quantum devices, diamond stands out among numerous quantum materials due to its exceptional optical, mechanical, and electronic properties. It is one of the few materials capable of achieving stable manipulation of quantum states at room temperature, thus playing an irreplaceable role in the construction of high-performance quantum information processing systems. Notably, the nitrogen-vacancy (NV) color center in diamond—a point defect formed by a nitrogen atom and an adjacent lattice vacancy—exhibits extraordinary magnetic sensitivity at room temperature. This unique characteristic stems from its ability to realize precise manipulation of quantum states through laser polarization and microwave regulation, enabling high-precision measurement of weak magnetic fields even in complex environments. This endows it with broad application prospects in biomedicine, geological exploration, and industrial detection.

In power systems, traditional magnetometers based on the principle of electromagnetic induction have long faced inherent limitations. For instance, they struggle to balance high precision and a wide measurement range, suffer from significant temperature drift during long-term operation, and are difficult to miniaturize for integration into smart grid sensor networks. These drawbacks severely hinder the advancement of intelligent monitoring of power grids, especially in scenarios such as high-precision DC current measurement and real-time status monitoring of power equipment. Against this backdrop, research on quantum magnetometers based on diamond NV color centers holds substantial scientific value and practical significance. It not only offers a novel technical pathway to overcome the bottlenecks of existing measurement technologies but also promotes the development of intelligent, integrated, and low-power-consumption measurement equipment. Furthermore, in-depth exploration of NV color center technology advances the practical application of quantum sensing, bridges the gap between fundamental quantum research and engineering applications, and lays a solid foundation for the innovative development of QIT in engineering fields such as energy, aerospace, and intelligent manufacturing.

This study first introduces the basic structure of NV centers and the principles of magnetic measurement (Fig. 1), with a particular focus on the continuous wave optical detection of magnetic resonance (CW-ODMR) method. It then details the fabrication processes of NV center diamonds, including high-pressure high-temperature (HPHT) synthesis (Fig. 4) and chemical vapor deposition (CVD) methods (Fig. 5), as well as subsequent processing steps. The advantages of ensemble diamond parameters are also discussed. Subsequently, the framework of the quantum magnetometer system is elaborated (Fig. 7), and the integration and development of quantum magnetometers are reviewed (Fig. 10). The current fabrication methods of diamond quantum magnetometers are summarized, highlighting the overall trends toward system integration, probe miniaturization, high sensitivity, and low power consumption. In the latter part of the paper, the current status of current sensors is detailed (Table 4). Traditional current transformers face certain limitations in achieving high-precision measurement, a wide dynamic range, and miniaturization of measurement probes, which significantly constrain the progress of smart grid research. To address these challenges, the application of quantum current transformers (QCTs) based on NV centers (Fig. 11) is introduced, and their use in power grid current transformers is explored, offering a novel solution for current monitoring. This study also compares different QCTs (Table 5) and further demonstrates the multifaceted application potential of diamond NV center quantum devices. Finally, the existing challenges of NV center magnetometers are discussed, and future research directions are proposed.

Research on diamond NV center-based quantum magnetometers has made steady progress. The room-temperature quantum manipulation capability, high magnetic sensitivity, and relative stability in complex environments of these magnetometers have alleviated some of the limitations of traditional magnetometers and laid the foundation for high-precision magnetic field measurements—especially in power system monitoring. However, current challenges remain, including the high cost of high-quality diamond fabrication, difficulties in system miniaturization, and the need to improve measurement accuracy and noise suppression. Future efforts should focus on optimizing diamond growth and post-processing techniques to reduce costs and enhance the performance of NV ensembles, advancing system integration to improve portability and noise suppression capabilities, and exploring multi-physical-parameter sensing to expand application scenarios. These measures will facilitate the practical application of NV center technology in the field of quantum sensing.