Recently, a joint research team led by Associate Professor Naotaka Sekiguchi, Associate Professor Takayuki Iwasaki, and Professor Muko Hatano at Tokyo Institute of Technology announced that they have developed a diamond quantum sensor using nitrogen vacancy centers in diamond, successfully achieving high sensitivity detection of 9.4pT/√ Hz under low-frequency magnetic fields. The team stated that this technology has the potential to be applied to brain magnetic measurements that do not require large, high cost equipment such as magnetic shielding and coolant. In the future, this technology is expected to be applied to brain computer interfaces such as routine checks for brain activity. The relevant research results were published in the journal Physical Review Applied.

Diamond is highly favored in the field of quantum sensing

At present, diamond quantum sensors have also become one of the forefront fields of international quantum competition. Western countries such as the United States, the United Kingdom, and the European Union have identified NV center quantum control and quantum sensor applications as key areas of support.

Diamond has long been favored in the field of quantum sensing due to its coherent nitrogen vacancy (NV) centers, adjustable spin, magnetic field sensitivity, and ability to operate at room temperature. This is because diamond itself has extremely high chemical stability and physical durability, making it the hardest and most thermally conductive material in the world. This also makes diamond quantum sensors very suitable for long-term applications in harsh environments.

At room temperature, diamond quantum sensors can perform highly sensitive measurements even in strong magnetic fields, making them promising for brain magnetic measurements that do not require large, expensive equipment such as magnetic shielding and cooling agents.

In November last year, a team from Tokyo Institute of Technology in Japan developed a diamond quantum sensor that can increase the range of electric vehicles by about 10%. The team stated that this technology can accurately measure the stored power, thereby maximizing the performance of in car batteries. Their goal is to put this technology into practical application as early as 2030.

Professor Muko Hatano from Tokyo Institute of Technology once stated that the biggest cost factor is diamond. The diamond used to manufacture quantum sensors is artificially synthesized, which is different from natural diamonds extracted from mines and used in jewelry. The use of inexpensive circuit boards and the mass production method of extracting diamonds from biogas can significantly reduce manufacturing costs.    

Realize the world's highest sensitivity low-frequency magnetic field measurement

Now, the team has once again innovated in the field of diamond quantum sensors.

This time, the research team has developed a diamond quantum sensor that is designed to be closer to the measurement object. It is achieved by synthesizing high-quality diamond with long spin phase relaxation time that determines magnetic field sensitivity, and reducing noise to the limit of quantum mechanics.

 This single diamond quantum sensor can achieve the highest sensitivity in the low-frequency region without the need for a magnetic flux concentrator. At the same time, it maintains superior stability and can operate continuously with high sensitivity for at least 200 minutes.

Associate Professor Guan Kou stated, "Achieving high sensitivity of diamond quantum sensors is an important step towards applications such as conventional magnetoencephalography. In future research, we will further explore methods to improve sensitivity and practicality. We also plan to apply the developed sensors to animal research to verify the effectiveness of diamond quantum sensors in magnetoencephalography." In addition, the University of Tokyo, the National Institute for Materials Science (NIMS) Electronic and Optical Functional Materials Research Center, the Quantum Science and Technology Research and Development Institute (QST) Takasaki Quantum Application Research Institute Quantum Function Creation Research Center, and the Ministry of Education, Culture, Sports, Science and Technology jointly participated in the research.

Source: Sensor Expert Network