提高激光抽运铯原子磁力仪灵敏度的研究

本文报道了一种基于激光抽运射频共振的铯原子磁力仪. 通过圆偏振光将铯原子抽运到暗态, 实现偏极化. 外磁场存在时, 原子磁矩将以拉莫尔频率绕外磁场进动. 在共振射频磁场的作用下, 原子被去极化而重新吸收光子. 通过探测出射光光谱可以测得拉莫尔频率进而得到外磁场的信息. 本文通过运用自制的894 nm 外腔半导体激光器, 建立了激光稳频装置和低噪声磁场测量环境, 实现了一种基于铯原子激光抽运射频共振的磁力仪. 通过磁力仪参数优化以及闭环测量, 磁力仪测量的外磁场达到了19 fT/Hz^1/2的极限灵敏度和1.8 pT/Hz^1/2的本征灵敏度, 空间分辨率小于2 cm. 关键词： 光抽运 塞曼效应 光探测磁共振 磁力仪

Study on the sensitivity of laser-pumped cesium atomic magnetometer

A cesium atomic magnetometer based on laser-pumped rf resonance has been investigated and demonstrated experimentally. Atoms are polarized and pumped to dark states by circularly polarized light. When there exists a magnetic field, the corresponding magnetization will be precessing around the magnetic field at Larmor frequency. By means of adding a resonant rf magnetic field, the atoms will be depolarized and absorb photons again. By detecting the spectrum of the transmitted light, one can obtain the information about the external magnetic field. We build an 894nm external cavity diode laser with a frequency stabilization device, and a low noise magnetic field measurement environment. After the optimization of the magnetometer parameter and closed-loop measurement, an ultimate sensitivity of 19 fT/Hz^1/2 and an intrinsic sensitivity of 1.8 pT/Hz^1/2 have been achieved with the spatial resolution smaller than 2 cm.
Keywords： optically pumping Zeeman effect ODMR magnetometer