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Low-Frequency Magnetic Sensing Using Magnetically Modulated Microcavity Resonant Mode
Xinrong Yang1, Jiamin Rong2, Enbo Xing1
1Key Laboratory of Dynamic Testing Technology, School of Instrument and Electronics, North University of China, Taiyuan 030051, China.
Abstract:
We propose a low-frequency magnetic sensing method using a magnetically modulated microcavity resonant mode. Our magnetically sensitive unit with periodically changing magnetic poles is formed by combining an AC excitation coil with a microcavity. The microcavity vibrates at the frequency of the AC amplitude-modulated signal and changes its resonant mode when the sensing unit interacts with a low-frequency magnetic field. Signal processing is performed on the resonant spectrum to obtain low-frequency magnetic signals. The results of the experiment show that the measured sensitivity to a 0.5 Hz magnetic field is 12.49 V/mT, and a bias instability noise of 16.71 nT is achieved. We have extended the measurable frequency range of the whispering gallery mode microcavity magnetometer and presented a development in microcavity magnetic sensing and optical readout.
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