AC field modulated DC magnetic field sensor based on optical whispering gallery mode microcapillary resonator

Area of Science:

• Optoelectronics
• Magnetometry
• Materials Science

Background:

• Developing sensitive DC magnetic field sensors is crucial for various industrial applications, including current and position detection.
• Existing sensors often face limitations in sensitivity, detection range, or operating conditions.
• Optical whispering gallery mode resonators offer potential for high-precision sensing due to their unique light confinement properties.

Purpose of the Study:

• To develop a highly sensitive DC magnetic field sensor.
• To investigate the performance of an optical whispering gallery mode microcapillary resonator-based sensor.
• To compare the sensor's sensitivity with existing DC magnetic field sensing technologies.

Main Methods:

• Constructing a sensor by integrating an optical whispering gallery mode microcapillary resonator with a magnetostrictive material.
• Measuring the signal-to-noise ratio of an AC-modulated magnetic field.
• Characterizing the sensor's DC magnetic field sensitivity and linear detection range in an unshielded environment at room temperature.

Main Results:

• Achieved a DC magnetic field sensitivity of 0.1703dB/Oe.
• Demonstrated a linear detection range from 4.8 Oe to 65.7 Oe.
• The sensor's sensitivity is approximately 2.3 times higher than other reported DC magnetic field sensors using similar materials.

Conclusions:

• The developed optical whispering gallery mode resonator sensor offers a novel and highly sensitive scheme for DC magnetic field detection.
• The sensor exhibits stable operation over a temperature range of [-11~45]°C with frequency adjustment.
• This technology holds promise for future industrial applications in current and position sensing.