基于交叉偏置磁场的单光束三轴原子磁力仪

Single-Beam Triaxial Atomic Magnetometer Based on Cross Bias Magnetic Field

报道了一种基于交叉偏置磁场的单光束单调制三轴原子磁力仪。基于Bloch方程研究了单光束泵浦探测结构实现三轴磁场检测的理论,提出使用交叉偏置磁场来旋转原子自旋极化方向实现三轴磁场探测的方案,并通过实验进行了验证。仅采用单一调制磁场,在抑制低频噪声的前提下避免了磁场串扰问题。实验结果表明:在零磁场环境下,系统对X轴方向待测磁场的响应带宽为90 Hz,系统灵敏度为21 fT/(Hz^(1/2));在Z轴方向施加34 nT的偏置磁场时,系统对Y轴方向待测磁场的响应带宽为130 Hz,系统灵敏度为26 fT/(Hz^(1/2));在Y轴方向施加38 nT的偏置磁场时,系统对Z轴方向待测磁场的响应带宽为128 Hz,系统灵敏度为29 fT/(Hz^(1/2))。该三轴原子磁力仪体积小、结构简单且制作成本低,有望应用于生物医疗等领域。

We report a single-beam triaxial atomic magnetometer based on cross bias magnetic field.Based on Bloch equation,the theory of single-beam scheme to achieve triaxial magnetic field detection is studied.To achieve triaxial magnetic field detection,the method of using cross bias magnetic field to rotate the atomic spin polarization direction is proposed and experimentally verified.By using only one single modulation magnetic field,it is possible to suppress low frequency noise and avoid the problem of magnetic field cross-talk.The experimental results show that the system response bandwidth to the magnetic field along X-axis is 90 Hz and the system sensitivity is 21 fT/(Hz^(1/2))under the zerofield condition.The system response bandwidth to the magnetic field along Y-axis is 130 Hz and the system sensitivity is 26 fT/(Hz^(1/2))when a bias magnetic field of 34 nT is applied in the Z-axis.The system response bandwidth to the magnetic field along Z-axis is 128 Hz and the system sensitivity is 29 fT/(Hz^(1/2))when a bias magnetic field of 38 nT is applied in the Y-axis.The proposed triaxial atomic magnetometer has the advantages of small size,simple structure and low fabrication cost,and is expected to be used in the biomedical and other fields.