Improving the sensitivity of an optically pumped rubidium atomic magnetometer by using of a repumping laser beam
Improving the sensitivity of an optically pumped rubidium atomic magnetometer by using of a repumping laser beam
复制标题
DOI：
10.7498/aps.70.20210920
复制
发表时间：
2021-12-05
影响因子：
1
通讯作者：
Wang Jun-Min
中科院分区：
文献类型：
--
作者：
Zhang Lu-Lu;Bai Le-Le;Wang Jun-Min
在光泵原子磁力仪的实验实现中，要求磁共振信号具有窄线宽和高信噪比（SNR）以实现高灵敏度。用795 nm激光作为泵浦和探测激光，比较了不同铷原子蒸气室的磁共振信号，研究了磁共振信号随温度的变化。优化的磁共振信号是用石蜡包被的铷原子蒸气室实现的。然后采用铷原子D2线780 nm激光作为再泵浦激光，研究了在不同的泵浦功率和再泵浦功率下磁共振信号的线宽和信噪比的变化。由于780 nm再泵浦激光束的作用，795 nm泵浦激光束使更多的铷原子自旋极化，从而显著提高了铷原子磁共振信号的幅度。与此同时，铷-85磁共振信号的线宽大致不再加宽。我们实现了一台带宽接近1.2 kHz的闭环光泵铷-85原子磁力计，仅用795 nm的泵浦激光束就将灵敏度校准为接近245.5 pT/Hz（1/2）。由于采用了780 nm的再泵浦激光束，灵敏度提高到接近26.4 pT/Hz（1/2），大约提高了一个数量级。我们还利用增强的铷磁共振信号校准了一台商用磁通门磁力仪的测量精度和偏差。
For the experimental implementation of an optically pumped atomic magnetometer, the magnetic resonance signal with a narrow linewidth and a high signal-to-noise ratio (SNR) is required for achieving a high sensitivity. Using 795-nm laser as both the pumping and the probe laser, we compare the magnetic resonance signals from different rubidium atomic vapor cells and investigate the variations of magnetic resonance signals with temperature. Optimized magnetic resonance signal is achieved with a paraffin-coated rubidium atomic vapor cell. Then the 780-nm laser at rubidium D2 line is introduced as a repumping laser, and we explore the changes of linewidth and SNR of the magnetic resonance signal under different power of the pumping laser and the repumping laser. Owing to the 780-nm repumping laser beam, the signal amplitude of rubidium-85 magnetic resonance signal is improved remarkably because more rubidium-85 atoms are spin- polarized by the 795-nm pumping laser beam. At the same time, the linewidth of rubidium-85 magnetic resonance signal is roughly not broadened anymore. We realize a closed-loop optically pumped rubidium-85 atomic magnetometer with a bandwidth of similar to 1.2 kHz, and the sensitivity is calibrated to be similar to 245.5 pT/Hz(1/2) only with the 795-nm pumping laser beam. Owing to the employment of the 780-nm repumping laser beam, the sensitivity is improved to be similar to 26.4 pT/Hz(1/2) which is improved roughly by one order of magnitude. We also calibrate the measurement accuracy and deviation of a commercial fluxgate magnetometer by using the enhanced rubidium magnetic resonance signal.