Abstract The negatively charged nitrogen vacancy (NV) color center in diamond is a type of point defect, which is extensively studied as a promising high‐sensitivity solid‐state magnetic field sensor. However, its transition from research to application is still limited due to the technical challenges of an integrated physical package. Here, an integrated diamond sensor is demonstrated with the essential component on the order of mm 3 , which is realized by a standard microfabrication process. A microfabrication‐compatible light guiding structure is constructed, providing photon detection efficiency of 66% and thus enabling a magnetic field detection sensitivity reaching 203 pT·Hz 1/2 . Incorporation of the sensor device with a magnetic yoke enables high‐precision wide‐range direct‐current sensing with current isolation. A current measuring range of 0–400 A with a minimum detection limit of 2 mA is achieved. By utilizing dual spin resonance modulation, the temperature drift is suppressed from 219 to 1.92 ppm∙°C −1 . This configuration provides new possibilities as a robust and scalable platform for current quantum sensing technologies.
Abstract The negatively charged nitrogen vacancy (NV) color center in diamond is a type of point defect, which is extensively studied as a promising high‐sensitivity solid‐state magnetic field sensor. However, its transition from research to application is still limited due to the technical challenges of an integrated physical package. Here, an integrated diamond sensor is demonstrated with the essential component on the order of mm 3 , which is realized by a standard microfabrication process. A microfabrication‐compatible light guiding structure is constructed, providing photon detection efficiency of 66% and thus enabling a magnetic field detection sensitivity reaching 203 pT·Hz 1/2 . Incorporation of the sensor device with a magnetic yoke enables high‐precision wide‐range direct‐current sensing with current isolation. A current measuring range of 0–400 A with a minimum detection limit of 2 mA is achieved. By utilizing dual spin resonance modulation, the temperature drift is suppressed from 219 to 1.92 ppm∙°C −1 . This configuration provides new possibilities as a robust and scalable platform for current quantum sensing technologies.
Negatively charged nitrogen-vacancy (NV) centers in diamond have been extensively studied as a promising high sensitivity solid-state magnetic field sensor at room temperature. However, their use for current sensing applications is limited due to the challenge of integration and miniaturization of the diamond NV sensor. Here, we demonstrate an integrated NV sensor fabricated with standard microfabrication process. The sensor device incorporated with a toroidal magnetic yoke enables a high-precision wide range direct current sensing with galvanic isolation. The performance of the diamond NV current sensor in an open loop configuration has been investigated. A current measuring range of 0 A ~ 1000 A with an uncertainty of 46 ppm are achieved. Taking advantage of dual spin resonance modulation, temperature drift is suppressed to 10 ppm/K. This configuration opens new possibilities as a robust and scalable platform for current quantum sensing technologies.
The research focuses on the solid-state spin system of diamond NV (Negatively Charged Nitrogen Vacancy, NV) color centers, which exhibit excellent optical readout, polarization properties, and millisecond-scale coherent time. This makes it an important means to achieve quantum information processing and quantum precision measurement. Additionally, its ultrahigh sensitivity to magnetic fields provides a potential path for diamond’s high-precision current measurement. This paper investigates a reliable method in the field of direct current measurement using quantum sensing technology based on diamond NV color centers. It involves measuring the change in the optically detected magnetic resonance spectrum based on a fixed microwave frequency to achieve magnetic field measurement. Simultaneously, by utilizing the spatial distribution of magnetic sensor heads, it achieves current inversion. Finally, an experimental platform was constructed for validation. Preliminary results indicate that the linear fit error for direct current amplitude is less than 10^-7, confirming the feasibility of this technological approach and providing a potential application for diamond in measuring currents in power systems.
Nitrogen vacancy (NV) centers in diamonds have emerged as one of the most promising candidates for magnetic field sensing. However, the laser intensity fluctuation is coupled to the diamond fluorescence; thus, the sensitivity is severely affected by the noise and stability of the laser. Integrating both the diamond quantum sensor and laser noise suppression device is a crucial step toward miniaturization and practical applications. Here, we present a piezoelectric-driven device to dynamically adjust the laser noise cancelation with dimensions of 5 × 5 × 1.5 mm 3 based on a grating interferometer. This device incorporates a grating structure to produce diffracted reference light with high-accuracy intensity modulation, actively tracking the fluorescence signal for differential common-mode rejection (CMR), effectively eliminating laser noise in the system, whereby the sensitivity of magnetic field detection is increased by a factor of 34, reaching 160 pT · Hz –1/2, and beneficial to the long-term stability. The compact design of this laser noise suppressor, in combination with a miniaturized diamond magnetometer, demonstrates its potential for high-precision magnetic field detection ability and strong portability.
Abstract Nitrogen-vacancy centers have demonstrated significant potential as quantum magnetometers for nanoscale phenomena and sensitive field detection, attributed to their exceptional spin coherence at room temperature. However, it is challenging to achieve solid-state magnetometers that can simultaneously possess high spatial resolution and high field sensitivity. Here we demonstrate nanoscale quantum sensing with high field sensitivity by using on-chip diamond micro-ring resonators. The ring resonator enables the efficient use of photons by confining them in a nanoscale region, enabling the magnetic sensitivity of 1.0 μT/√Hz on a photonic chip with a measurement contrast of theoretical limit. We also show that the proposed on-chip approach can improve the sensitivity via efficient light extraction with photonic waveguide coupling. Our work provides a pathway toward the development of chip-scale packaged sensing devices that can detect various nanoscale physical quantities for fundamental science, chemistry, and medical applications.
Point defects in diamond, particularly nitrogen-vacancy (NV) centers, have emerged as powerful tools for a broad range of quantum technologies. These defects are promising candidates for quantum information science, serving as deterministic single-photon sources and solid-state quantum memories. They have also been employed as nanoscale quantum sensors to detect various physical quantities, including magnetic fields, electric fields, and temperature, owing to their long spin coherence time at room temperature. Development of these diamond-based quantum technologies has been rapidly boosted by a recent quantum leap in nanofabrication technologies for high-quality single-crystal diamond. Incorporating these color centers into diamond nanostructures with mature integrated photonics provides a promising route to build scalable and practical systems for quantum applications. This review discusses recent progress and challenges in the hybrid integration of diamond color centers on cutting-edge photonic platforms. Nitrogen-vacancy centers in diamond have emerged as powerful tools for a broad range of quantum technologies. This review discusses recent progress and challenges in the hybrid integration of diamond color centers on cutting-edge photonic platforms.
In modern-day quantum metrology, quantum sensors are widely employed to detect weak magnetic fields or nanoscale signals. Quantum devices, exploiting quantum coherence, are inevitably connected to physical constants and can achieve accuracy, repeatability, and precision approaching fundamental limits. As a result, these sensors have shown utility in a wide range of research domains spanning both science and technology. A rapidly emerging quantum sensing platform employs atomic-scale defects in crystals. In particular, magnetometry using nitrogen-vacancy (NV) color centers in diamond has garnered increasing interest. NV systems possess a combination of remarkable properties, optical addressability, long coherence times, and biocompatibility. Sensors based on NV centers excel in spatial resolution and magnetic sensitivity. These diamond-based sensors promise comparable combination of high spatial resolution and magnetic sensitivity without cryogenic operation. The above properties of NV magnetometers promise increasingly integrated quantum measurement technology, as a result, they have been extensively developed with various protocols and find use in numerous applications spanning materials characterization, nuclear magnetic resonance (NMR), condensed matter physics, paleomagnetism, neuroscience and living systems biology, and industrial vector magnetometry. In this chapter, NV centers are explored for magnetic sensing in a number of contexts. In general, we introduce novel regimes for magnetic-field probes with NV ensembles. Specifically, NV centers are developed for sensitive magnetometers for applications where microwaves (MWs) are prohibitively invasive and operations need to be carried out under zero ambient magnetic field. The primary goal of our discussion is to improve the utility of these NV center-based magnetometers.