Emerging quantum technologies, such as quantum computations and precise sensing, provide new opportunities in the fields of science and engineering.While energy consumption is a major concern for modern industry and society, it is rarely taken into consideration for quantum technologies.Especially, the potential of quantum technologies directly powered by renewable energy has long been neglected.The initialization, manipulation, and readout of quantum systems generally require high-power-consuming equipment, such as a dilution refrigerator, a microwave-power amplifier, and a high-power laser.Here, we discover a direct utilization path for solar energy to steer the quantum states of negatively charged nitrogen-vacancy centers in diamond, which is one of the most promising solid-state quantum systems in the past decades.Following this method, we demonstrate sunlight-driven quantum magnetometry.The initialization and readout of this quantum magnetometry are achieved directly by sunlight, and conventional microwave manipulation can be removed by using a microwave-free scheme.By utilizing ambient energy directly, our method brings potential solutions to the energy-consumption issue of quantum technologies.This technique can be further extended to multiple quantum systems, and thus opens the door to environmentally sustainable quantum technologies and self-powered quantum sensing in the future.
Emerging quantum technologies, such as quantum computations and precise sensing, provide new opportunities in the fields of science and engineering.While energy consumption is a major concern for modern industry and society, it is rarely taken into consideration for quantum technologies.Especially, the potential of quantum technologies directly powered by renewable energy has long been neglected.The initialization, manipulation, and readout of quantum systems generally require high-power-consuming equipment, such as a dilution refrigerator, a microwave-power amplifier, and a high-power laser.Here, we discover a direct utilization path for solar energy to steer the quantum states of negatively charged nitrogen-vacancy centers in diamond, which is one of the most promising solid-state quantum systems in the past decades.Following this method, we demonstrate sunlight-driven quantum magnetometry.The initialization and readout of this quantum magnetometry are achieved directly by sunlight, and conventional microwave manipulation can be removed by using a microwave-free scheme.By utilizing ambient energy directly, our method brings potential solutions to the energy-consumption issue of quantum technologies.This technique can be further extended to multiple quantum systems, and thus opens the door to environmentally sustainable quantum technologies and self-powered quantum sensing in the future.
Nitrogen-vacancy (NV) centers in diamond have emerged as a robust room-temperature solid-state platform for weak magnetic field detection. Several NV-based magnetometers have been proposed in the past decades, but they still suffer from either low sensitivity or high power consumption. This is a challenge for sensors deployed in remote locations on Earth or in space that are not connected to the power grid. Although sunlight-driven quantum magnetometry, which does not rely on conventional energy sources, has been proposed as a possible solution, its sensitivity remains a limitation. Here, we present an impressive improvement in the sensitivity of the sunlight-driven NV-diamond quantum magnetometer. A crucial aspect of our approach involves leveraging the ground-state level anti-crossing properties of the NV centers, coupled with magnetic flux concentrators. This integration enables us to achieve a magnetic-field sensitivity of 26 pT/Hz in a laboratory environment and 49 pT/Hz when the magnetometer operates outdoors under sunlight. We also illustrate the promising potential of further improving the sensitivity to the subpicotesla level by using cutting-edge technologies. Furthermore, we reveal the capability of this quantum magnetometer as a receiver of extremely low-frequency magnetic signals and pave the way for communication applications. These advancements represent a significant leap toward attaining high-sensitivity and energy-efficient magnetic field sensing and expanding the range of possible applications for these environmentally sustainable quantum technologies.
Atomic magnetometers, a prominent class of quantum sensors, have become increasingly significant in magnetometry, with extensive applications in cutting-edge physics, biomedical imaging, industrial inspection, and beyond. However, the power consumption of an atomic magnetometer is primarily dominated by that demanded to heat the atomic vapor cell to its operating temperature. This operating temperature determines the alkali-metal atomic density, thereby influencing the magnetic field sensitivity and overall power consumption, which poses a potential obstacle to the large-scale engineering application of atomic magnetometers. In this article, a novel heating method utilizing renewable solar energy is proposed for the first time, which can surpass the limitation of conventional heating methods in thermo-atom-based quantum sensors. By exploiting an intelligent closed-loop control system to adaptively regulate the functionalized sunlight power, this proposed method has the capability of both high heating efficiency and accuracy. The heating properties and laser absorption spectrum at different temperatures up to 180 °C are characterized substantiating the feasibility of utilizing sunlight. Moreover, a sunlight-heated, highly sensitive, microfabricated atomic magnetometer with a magnetic field sensitivity of 18 fT/Hz1/2is demonstrated. And the single-chamber microelectromechanical system atomic vapor cell as the key component is fabricated by utilizing deep silicon micromachining and anodic bonding techniques. This proposed technique can be further extended to all quantum sensing systems based on thermal atomic ensembles and open up new possibilities for the development of self-powered, environmentally friendly quantum sensors.
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.
Quantum sensors encompass a diverse class of devices that exploit quantum coherence to detect weak or nanoscale signals. As their behavior is tied to physical constants, quantum sensors can achieve accuracy, repeatability, and precision approaching fundamental limits [1, 2]. As a result, these sensors have shown utility in a wide range of applications in both science and engineering leading to innovations. Among many solid-state spin systems, nitrogen-vacancy (NV) centers in diamonds have attracted considerable attention as a leading platform in many fields of quantum technologies, from quantum sensing to information processing and communication applications. They have superior physical properties, and their quantum coherence is preserved even at room temperature. The energy levels of NV centers are sensitive to magnetic fields, electric fields, strain, and temperature, and the spatial resolution is scalable from nanometers to millimeters. Therefore, diamond quantum sensors are distinctive sensors with multimodality and span scalable application fields. To realize an ideal quantum sensor for applications, the technical challenges in the sensor materials and the quantum control techniques, such as coherent microwave spin manipulation, effective optical spin-state initialization, and readout, have been developed. This chapter briefly explains the sensing principle using NV centers and then introduces sensor systems for biomedical applications, and monitoring of batteries for electric vehicles and internal power devices.
Quantum sensors based on nitrogen vacancy (NV) centers in diamond have been a central topic in the sensing community for more than a decade. The extraordinary properties at room temperature of the spin system in diamond have made it one of the most prominent quantum platforms for the development of commercial quantum sensors. In particular, the sensitivity of the electronic spin in NV centers has made diamond-based magnetic sensors of special interest for their potential application in medical, industrial or navigation solutions. However, the use of these sensors for universal vector magnetometry was constrained by the need for previous knowledge on the field being measured to fully exploit their benefits. In this work, we show a method to perform unconditional vector magnetometry without the need of external information on the magnetic field, based only on the spatial arrangement of the diamond and the microwave antenna combination. While previous NV-based vector magnetometry methods require partial knowledge of the magnetic field (e.g. a calibrated bias field), we exploit the possibilities of selecting particular directions of the spins in the diamond with elliptically polarized microwave fields. We prove that our method allows to estimate both magnitude and direction of external magnetic fields without further assumptions or constraints.
Abstract Solid state spins have demonstrated significant potential in quantum sensing with applications including fundamental science, medical diagnostics and navigation. The quantum sensing schemes showing best performance under ambient conditions all utilize microwave or radio-frequency driving, which poses a significant limitation for miniaturization, energy efficiency, and non-invasiveness of quantum sensors. We overcome this limitation by demonstrating a purely optical approach to coherent quantum sensing. Our scheme involves the 15N nuclear spin of the Nitrogen-Vacancy (NV) center in diamond as a sensing resource, and exploits NV spin dynamics in oblique magnetic fields near the NV’s excited state level anti-crossing to optically pump the nuclear spin into a quantum superposition state. We demonstrate all-optical free-induction decay measurements—the key protocol for low-frequency quantum sensing—both on single spins and spin ensembles. Our results pave the way for highly compact quantum sensors to be employed for magnetometry or gyroscopy applications in challenging environments.