Tang Junjian, Zhai Yueyang, Cao Li, Zhang Yaohua, Li Lin, Zhao Binbin, Zhou Binquan, Han Bangcheng, Liu Gang
Opt Express. 2021 May 10;29(10):15641-15652. doi: 10.1364/OE.425851.
We demonstrate a single-beam atomic magnetometer (AM) capable of measuring a three-axis magnetic field with high-sensitivity, achieved by applying a small DC offset field and a high frequency modulation field. To satisfy the miniaturization demand of AMs, an elliptically polarized light detuned by 50 GHz from the resonance transition center is employed. The circularly polarized component is used to polarize the alkali-metal atoms, while the linearly polarized light is used to detect the dynamics of the polarized spin under a magnetic field. Based on theoretical analysis, parameters that significantly affect the performance are optimized, and a sensitivity of 20 fT/Hz in x-axis, 25 fT/Hz in y-axis, 30 fT/Hz in z-axis is achieved with a miniature 4 × 4 × 4 mm Rb vapor cell. Moreover, we also verify that the operation principle of AMs can be used to null background magnetic fields in-situ with isotropic compensation resolution of 6.7 pT, which provides an effectively precise method for zeroing ambient magnetic field. The high-sensitivity operating of an elliptically-polarized-laser-based magnetometer provides prospective futures for constructing a compact, low-cost AM, which is particularly applicable for non-invasive bio-magnetic imaging such as array-based magnetoencephalography (MEG) and magnetocardiography (MCG).
我们展示了一种单光束原子磁力计（AM），它能够通过施加一个小的直流偏置场和一个高频调制场来高灵敏度地测量三轴磁场。为了满足原子磁力计的小型化需求，采用了与共振跃迁中心失谐50 GHz的椭圆偏振光。圆偏振分量用于极化碱金属原子，而线偏振光用于检测磁场下极化自旋的动力学。基于理论分析，对显著影响性能的参数进行了优化，使用微型4×4×4 mm的铷蒸汽池，在x轴上实现了20 fT/Hz的灵敏度，在y轴上为25 fT/Hz，在z轴上为30 fT/Hz。此外，我们还验证了原子磁力计的工作原理可用于原位消除背景磁场，各向同性补偿分辨率为6.7 pT，这为消除环境磁场提供了一种有效精确的方法。基于椭圆偏振激光的磁力计的高灵敏度运行，为构建紧凑、低成本的原子磁力计提供了前景，这尤其适用于基于阵列的脑磁图（MEG）和心磁图（MCG）等非侵入性生物磁成像。
