A kilohertz bandwidth and sensitive scalar atomic magnetometer using an optical multipass cell

High-frequency ultraweak magnetic field measurements are essential. We demonstrate a scalar rubidium atomic magnetometer with effective measurement bandwidth of kilohertz and sensitivity of subpicotesla operating at a temperature of 365 K in an ambient field of 50 mu T. The Faraday rotation signal is enhanced by a more simplified optical multipass cell compared to previous works. We developed an approach of continuous or burst sampling mode to maximize the frequency capability of the system, and propose a scheme of precise control pulse series as well as an analytical method of data processing. Experimental results show that high contrast atomic spin projection noise and free induction decay signal are observed, and a sampling rate of 2 kHz along with the sensitivity of 0.7 pT/Hz(1/2) between 20 and 1000 Hz have been achieved. It would help further research in physics and biomedical investigations that need high bandwidth magnetometers or sensor arrays in the earth's field.

Automated summary

This study presents a high-frequency ultraweak magnetic field measurement method using a scalar rubidium atomic magnetometer. The Faraday rotation signal is enhanced by a simplified optical multipass cell. By employing continuous or burst sampling mode and precise control pulse sequences, high contrast atomic spin projection noise and free induction decay signals were observed.