A Performance-Enhanced Closed-Loop SERF Atomic Magnetometer

Ziao Liu

doi:10.1109/JSEN.2024.3468009

2024-11-15

PRE

DOI：10.1109/JSEN.2024.3468009

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摘要

En 中文

The spin-exchange relaxation-free (SERF) atomic magnetometers (AMs) exhibit ultrahigh sensitivity in ultraweak magnetic field measurement, but their narrow bandwidth constrains the scope of their applications. To increase the bandwidth, magnetic field closed-loop control technology has been introduced into AMs with demonstrated efficacy. However, previous research on closed-loop AMs resulted in signal distortion problems, primarily due to imprecise closed-loop models and control parameters selection without theoretical support. This problem is specifically characterized by the unexpected amplification or reduction of signals at certain frequencies, directly leading to the degradation of the frequency performance of the closed-loop AM, making it unsuitable for applications requiring full-bandwidth measurement. In this study, we proposed a performance-enhanced closed-loop SERF AM, maximizing the bandwidth while ensuring consistent performance across the entire bandwidth. An accurate closed-loop system model was first established. Subsequently, an optimal relationship between the control parameters was proposed according to the eigenvalues of the closed-loop system, and the particle swarm optimization (PSO) algorithm was introduced to determine the optimal control parameters. The improved closed-loop system was constructed in a triaxial SERF AM, achieving an average bandwidth of 410 Hz and a sensitivity of 10 fT/Hz(1/2) in three axes, while ensuring consistent performance across the entire bandwidth. With the proposed method, the optimized control parameters can be obtained only by requiring the frequency response of the open-loop AM, which is convenient and useful for closed-loop AM applications.

Keyword:

Bandwidth

Magnetic fields

Closed loop systems

Transfer functions

Magnetometers

Magnetic resonance

Magnetic field measurement

Frequency modulation

Frequency response

Frequency measurement

Closed-loop system