A Multi-Pass Optically Pumped Rubidium Atomic Magnetometer with Free Induction Decay

A free-induction-decay (FID) type optically-pumped rubidium atomic magnetometer driven by a radio-frequency (RF) magnetic field is presented in this paper. Influences of parameters, such as the temperature of rubidium vapor cell, the power of pump beam, and the strength of RF magnetic field and static magnetic field on the amplitude and the full width at half maximum (FWHM) of the FID signal, have been investigated in the time domain and frequency domain. At the same time, the sensitivities of the magnetometer for the single-pass and the triple-pass probe beam cases have been compared by changing the optical path of the interaction between probe beam and atomic ensemble. Compared with the sensitivity of similar to 21.2 pT/Hz(1/2) in the case of the single-pass probe beam, the amplitude of FID signal in the case of the triple-pass probe beam has been significantly enhanced, and the sensitivity has been improved to similar to 13.4 pT/Hz(1/2). The research in this paper provids a reference for the subsequent study of influence of different buffer gas pressure on the FWHM and also a foundation for further improving the sensitivity of FID rubidium atomic magnetometer by employing a polarization-squeezed light as probe beam, to achieve a sensitivity beyond the photo-shot-noise level.

Automated summary

This paper presents a free-induction-decay type optically-pumped rubidium atomic magnetometer driven by a radio-frequency magnetic field. The influences of different parameters on the FID signal amplitude and FWHM have been investigated. The sensitivities of the magnetometer for single-pass and triple-pass probe beam cases have been compared, showing that the triple-pass probe beam significantly enhances the FID signal amplitude and sensitivity.