Optically-pumped magnetometer (OPM) has been of increasing interest for biomagnetic measurements due to its low cost and portability compared with superconducting quantum interference devices (SQUID). Miniaturized spin-exchange-relaxation-free (SERF) OPMs typically have limited bandwidth (less than a few hundred Hertz), making it difficult to measure high-frequency biomagnetic signals such as the magnetocardiography (MCG) signal of the mouse. Existing experiments mainly use SQUID systems to measure the signal. In this paper, we introduce a prototype miniaturized single-beam SERF magnetometer with a bandwidth of ∼ 1 kHz. Instead of operating the OPM in a closed-loop mode to improve the bandwidth of the OPM, which usually has a poorer performance in high-frequency range, we use the power-broadening effects to shorten the spin relaxation time and thus a faster response to the magnetic fields to be measured. Combined with light power stabilizations to improve both the sensitivity and stability, our magnetometer has a low noise floor of 30 fT / Hz, which has been successfully adopted to measure the MCG signal of the mouse.
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http://dx.doi.org/10.1364/BOE.545624 | DOI Listing |
Biomed Opt Express
January 2025
State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Electronics, and Center for Quantum Information Technology, Peking University, Beijing 100871, China.
Optically-pumped magnetometer (OPM) has been of increasing interest for biomagnetic measurements due to its low cost and portability compared with superconducting quantum interference devices (SQUID). Miniaturized spin-exchange-relaxation-free (SERF) OPMs typically have limited bandwidth (less than a few hundred Hertz), making it difficult to measure high-frequency biomagnetic signals such as the magnetocardiography (MCG) signal of the mouse. Existing experiments mainly use SQUID systems to measure the signal.
View Article and Find Full Text PDFNeuroimage
January 2025
Key Laboratory of Ultra-Weak Magnetic Field Measurement Technology, Ministry of Education, School of Instrumentation and Optoelectronic Engineering, Beihang University, 100191, Beijing, China; Hangzhou Institute of Extremely-Weak Magnetic Field Major National Science and Technology Infrastructure, Hangzhou, 310051, China; State Key Laboratory of Traditional Chinese Medicine Syndrome/Health Construction Center, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, 510120, China; Hefei National Laboratory, Hefei, 230088, China. Electronic address:
The optically pumped magnetometer (OPM) based magnetoencephalography (MEG) system offers advantages such as flexible layout and wearability. However, the position instability or jitter of OPM sensors can result in bad channels and segments, which significantly impede subsequent preprocessing and analysis. Most common methods directly reject or interpolate to repair these bad channels and segments.
View Article and Find Full Text PDFBioengineering (Basel)
December 2024
Key Laboratory of Ultra-Weak Magnetic Field Measurement Technology, Ministry of Education, School of Instrumentation and Optoelectronic Engineering, Beihang University, 37 Xueyuan Rd., Haidian District, Beijing 100083, China.
Optically pumped magnetometer magnetoencephalography (OPM-MEG) represents a novel method for recording neural signals in the brain, offering the potential to measure critical neuroimaging characteristics such as effective brain networks. Effective brain networks describe the causal relationships and information flow between brain regions. In constructing effective brain networks using Granger causality, the noise in the multivariate autoregressive model (MVAR) is typically assumed to follow a Gaussian distribution.
View Article and Find Full Text PDFNeuroimage
January 2025
Key Laboratory of Ultra-Weak Magnetic Field Measurement Technology, Ministry of Education, School of Instrumentation and Optoelectronic Engineering, Beihang University, 100191, Beijing, China; Hangzhou Institute of Extremely-Weak Magnetic Field Major National Science and Technology Infrastructure, Hangzhou, 310051, China; State Key Laboratory of Traditional Chinese Medicine Syndrome/Health Construction Center, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, 510120, China; Hefei National Laboratory, Hefei, 230088, China. Electronic address:
J Neural Eng
January 2025
Biomagnetic Imaging Laboratory, University of California, San Francisco, 513 Parnassus Avenue, S362, San Francisco, CA 94143, United States of America.
electroencephalography (EEG) and magnetoencephalography (MEG) are widely used non-invasive techniques in clinical and cognitive neuroscience. However, low spatial resolution measurements, partial brain coverage by some sensor arrays, as well as noisy sensors could result in distorted sensor topographies resulting in inaccurate reconstructions of underlying brain dynamics. Solving these problems has been a challenging task.
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