A research group at Perm Polytechnic University has presented a new design of a compact optical magnetometer designed for use in aviation navigation and geological exploration. The development makes it possible to increase the accuracy and simplify the design of the device, which is especially important in conditions of Russia’s dependence on the import of such devices and the need to create domestic high-tech solutions.
Magnetometers are devices that measure magnetic fields. They are widely used to search for minerals, detect metals, correct the course of aircraft, as well as in medical diagnostics, for example, to monitor the condition of the heart and brain. In geological exploration and aviation, optical magnetometers are of particular importance, capable of detecting anomalies in the Earth’s magnetic field, which makes it possible to identify ore deposits or adjust aircraft navigation.
Technological features
Traditional optical magnetometers use a long (up to 1 km) optical fiber rolled into a coil. The Perm Polytechnic team proposed replacing it with a short (10 m) piece of SPUN fiber enclosed in an annular optical resonator. This scheme allows light to pass through the ring multiple times, which provides the necessary sensitivity with significantly smaller dimensions of the device. This solution significantly simplifies the design and reduces the weight of the device, which is important for mobile and aviation applications.
To increase the sensitivity of the magnetometer, the effect of light polarization is used: the device requires “swirled” (circular) light, which is traditionally formed using a separate crystal plate. In the new design, the scientists discarded this additional detail by combining two types of optical fibers. At their junction, linear polarization is automatically converted to circular polarization, which makes it easier and cheaper to manufacture the sensor.
Experimental results and prospects
During the experiments, the SPUN fiber successfully detected magnetic fields with an induction of 0.01 T, which is about 200 times weaker than that of a household magnet. This sensitivity makes the device in demand for metal quality control, searching for metal objects underground, and in aviation navigation, where detection of magnetized parts or hidden obstacles is required.
The development was supported by the Ministry of Science and Higher Education of the Russian Federation (project No. FSNM-2023-0006), and the results were published in the Bulletin of the Russian Academy of Sciences: Physics (volume 88, 2024).
The researchers note that further improvement of the technology will increase the sensitivity of the magnetometer, opening up opportunities for its use in medical diagnostics. In the future, domestic compact magnetometers can become a competitive alternative to their foreign counterparts, combining high accuracy and small size.