基于腔增强的磁光旋转铯原子磁强计

Cesium Atomic Magnetometer Based on the Cavity-enhanced Magneto-optic Polarization Rotation

谐振腔通过增加光与原子相互作用的长度而增大探测光偏转角,大大增强了原子磁强计的灵敏度.我们基于磁光旋转的铯原子磁强计,在理论与实验上研究了磁场测量灵敏度的腔增强因子与腔镜反射率的关系,得到在一定原子气室损耗条件下获得最优磁测灵敏度的最佳腔镜反射率.利用平凹驻波腔,在特定的腔镜反射率,原子气室对光功率的损耗分别为9.5%和8.5%,对应的腔逃逸效率为38%和41%,腔对磁场灵敏度的增强因子为4.4和5.1;在保持光与原子相互作用强度的情况下,随着原子气室对光场损耗的降低,磁场灵敏度进一步增强,腔增强效果更显著.

The cavity increases the rotation angle by increasing the length of the interaction between probe light and atoms,which greatly improves the sensitivity of a magnetometer.On an atomic magnetometer based on the non-linear magneto-optical effect,we have theoretically and experimentally studied the relationship between the enhancement factor of the sensitivity and the reflectivity of the cavity mirror,and obtained the optimal sensitivity with certain loss of probe light in atomic vapor cell.In a plano-concave standing-wave cavity,when the reflectivity of the input mirror and output coupling mirror is respectively 99.5%and 88%,the loss of the light intensity of the atomic vapor cell is 9.5%and 8.5%;and the corresponding cavity escape efficiencies are 38%and 41%;the enhancement factor of the sensitivity with cavity is 4.4 and 5.1.Ensuring the strength of the interaction between light and atoms,as the loss of the probe light in cell comes down,the sensitivity of the magnetometer is improved,and the cavity enhancement effect is more significant.