Magnetocardiography Measurements by Microfabricated Atomic Magnetometer With a 3-D Spherical Alkali Vapor Cell

Abstract

In the field of biomagnetic applications, including magnetocardiography (MCG), portable magnetic measurement is promising. This article demonstrates simulated MCG measurements using a microfabricated spin-exchange relaxation-free (SERF) atomic magnetometer with a 3-D chip-scale spherical rubidium vapor cell. The vapor cell temperature is optimized from 100 °C to 160 °C, and the magnetometer response is recorded under different magnetic flux densities 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 microfabricated magnetometer in the magnetic shield exhibits a sensitivity of 125 fT/Hz1/2 at 15 Hz, and the signal-to-noise ratio is increased to 48.3 after denoising. The magnetometer enabled by a 3-D 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 microfabricated atomic magnetometers based on chip-scale 3-D alkali vapor cells have the potential to enable magnetoencephalography (MEG) measurements and nuclear magnetic resonance imaging (NMRI).