Abstract
The spin self-sustaining atomic magnetometer has the advantage of 1/τ measurement and great development potential in many applications. In this paper, we investigated the main elements that affect the stability and accuracy of the self-sustaining magnetometer and proposed the methods to improve its performance based on the measurement results. The correlation coefficient between fluctuations of the magnetic field generated by coils and the spin Larmor precession frequency is 0.97, which mainly dominates the stability in a short term. The accuracy of the magnetometer is affected by the power and frequency of the pump light. The Larmor precession frequency coefficient related to the pump light power is 26 mHz/mW, and the effect on the Larmor precession frequency is minimized when the pump light frequency is red detuned by 200 MHz from the 85Rb transition D1 line F = 3 to F′ = 3. The 1/τ measurement time after these corrections can be extended to 10 s, and the sensitivity achieved is 149 fT/Hz, which is close to the quantum projection noise limit of the system.
Highlights
High precision magnetic field measurements based on the optically pumped atomic systems by monitoring the Larmor precession frequency of the spins are the key to realize various applications
The Larmor precession frequency coefficient related to the pump light power is 26 mHz/mW, and the effect on the Larmor precession frequency is minimized when the pump light frequency is red detuned by 200 MHz from the 85Rb transition D1 line F = 3 to F′ = 3
Over the past half century, the atomic magnetometers have approached or even surpassed the levels of sensitivity attained by state-of-the-art superconducting quantum interference devices (SQUIDs)1–6 and are well integrated
Summary
High precision magnetic field measurements based on the optically pumped atomic systems by monitoring the Larmor precession frequency of the spins are the key to realize various applications. In the areas such as geophysics, resource exploration, navigation, bio-science, medicine, and fundamental physics, it is usually advantageous to use the smallest and highest sensitive possible sensor. Over the past half century, the atomic magnetometers have approached or even surpassed the levels of sensitivity attained by state-of-the-art superconducting quantum interference devices (SQUIDs) and are well integrated. A main limitation to the sensitivity of these quantum systems is the coherence time of the atomic spins τ0,10 δB ≈ √ (1). Many methods are investigated to improve the sensitivity performance through two aspects: one is increasing the coherence time τ√0, while the other is developing new methods that can surpass the 1/ τ rule at a timescale larger than τ0
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