Probing Atomic Magnetism

Ana María Rey

Yibo Qi, Shuying Wang, Nuozhou Xu +3 more

Multi-passed probe light can enhance the signal of atomic magnetometers by increasing the effective optical path length between the alkali metal atomic ensemble and the probe light, thereby strengthening the sensitivity. In recent years, multi-passed probe light has become an important method for improving the response signal and sensitivity of atomic magnetometers. To achieve biaxial magnetic field measurement while maintaining high sensitivity, a biaxial measurement spin-exchange relaxation-free (SERF) atomic magnetometer with a multi-passed probe light is proposed in this paper. The theoretical model and experimental advantages of using multi-passed probe light in longitudinal magnetic field modulation (Z-mode) SERF atomic magnetometers are analyzed. In this paper, a new model of output response of the Z-mode SERF atomic magnetometer based on multi-passed probe light is established, a compact reflective optical path is designed to increase the optical path between the probe light and the polarized alkali metal atomic ensemble, enhance the signal response, and achieve the suppression of low-frequency 1/f noise through longitudinal magnetic field modulation. Experimental results confirmed that the magnetic field sensitivity in the x- and y-axis of the multi-passed probe light configuration improved by 29% and 18%, respectively, compared to the single-pass configuration.

J. Stajic

Qian Cao, Yueyang Zhai, Binyue Huang +2 more

Introduction: A spin exchange relaxation free atomic magnetometer, as an ultra-highly sensitive magnetic field sensor, is limited by the performance of the probe laser system. The probe laser pumping effect (PLPE) hinders the increase in the performance of probe laser system. Methods: This study investigated the PLPE and proposed a method for suppressing the same. Through changes to the angle of a quarter wave plate and the addition of a triangular modulated magnetic field to the alkali atoms, the suppression point was determined. Results and discussion: Further, related parameters were measured for different degree of polarizations of the probe laser, which confirmed that the influence of PLPE on the magnetic field was the least at the suppressed point.

Zhigang Feng, Xiaochi Liu, Zhenfei Song +1 more

We demonstrate a multi-parameter sensing scheme for free space microwave electric and magnetic fields in single vapor cell based on the atom-based microwave detection techniques. A weak probe laser though a rubidium vapor cell first acts as magnetic probe to measure the microwave magnetic field via atomic Rabi resonance of the ground state hyperfine transition. When another strong coupling laser is subsequently counter-propagated and overlapped with the probe laser in the same atomic vapor cell, the probe laser is then used as electric probe to measure microwave electric field by off-resonant microwave dressed Rydberg Autler-Townes splitting. We achieve measurement of microwave electric and magnetic fields without any complicated tuning methods at the clock frequency of 6.835 GHz. Based on the inherent relationship between microwave electric and magnetic fields, and their good linear response characteristics in respective suitable power ranges, the equivalent microwave magnetic fields are derived from linear fitting of the measured electric fields, which are in agreement with the calibrated experimental results within the same power range. This work provides an effective approach for extending the power dynamic range of atom-based microwave quantum sensors.