Magnetocardiography Measurements by Microfabricated Atomic Magnetometer With a 3-D Spherical Alkali Vapor Cell
Jin Zhang, Kangni Liu, Jianfeng Zhang, Ziji Wang, Jintang Shang
Abstract
In the field of biomagnetic applications, including magnetocardiography (MCG), portable magnetic measurement is promising. This paper demonstrates simulated MCG measurements using a micro-fabricated spin-exchange relaxation-free (SERF) atomic magnetometer with a 3D chip-scale spherical rubidium vapor cell. The vapor cell temperature is optimized from 100 to 160 °C, and the magnetometer response is recorded under different magnetic flux density in the range of 10-122 pT. Then simulated MCG measurements are implemented in a magnetic shield. The original MCG signals are denoised by a two-step processing to obtain the featured waveforms of the MCG signals. The experimental result shows that the micro-fabricated magnetometer in the magnetic shield exhibits a sensitivity of 125 fT/Hz1/2 at 15Hz, and the signal-to-noise ratio is increased to 48.3 after denoising. The magnetometer enabled by a 3D chip-scale spherical rubidium vapor cell has the ability to obtain morphologically clear cardiomagnetic signals with distinct P-,QRS-, and T-waves. With further optimizations, the micro-fabricated atomic magnetometers based on chip-scale 3D alkali vapor cells have the potential to enable magnetoencephalography (MEG) measurements and nuclear magnetic resonance imaging (NMRI).