基于激光偏振调制的全光Cs原子磁力仪研究

Research of all-optical Cs atomic magnetometer by using modulation of laser′s polarization

采取对激光左旋σ+偏振态和右旋σ-偏振态周期性调制产生共振的方法,实现对Cs原子拉莫尔进动频率的检测,取代了采用射频线圈产生共振的方法而实现了对磁场的全光检测,从而避免了传统光泵原子磁力仪信号串扰的问题。展示了该方法对原子磁矩在磁场中进动频率的检测原理,分析了该模式下的信号特征,根据信号特征设计了对拉莫尔进动信号的检测和处理系统。同相信号显示为洛伦兹线形;正交信号显示为色散线形,在共振频率处大小为0;相位信号显示为连续单调递减函数,在共振频率处大小为0。正交信号和相位信号均可以用来锁定共振频率点,实现磁场测量。

Modulation of laser′s left-handed and right-handed polarization was used in the paper.This method has realized all-optical detection of magnetic field and avoided cross talk existing in conventional atomic magnetometer.The detection principle of precession frequency of atomic magnetic moment in magnetic field was demonstrated based on the method,and the signal was analyzed,then the detection and processing system was designed based on the analysis.The in-phase signal was displayed as Lorenz lineshape.The quadrature signal was displayed as dispersion lineshape,and the magnitude was 0 at resonance frequency.The phase signal was displayed as monotonically decreasing function with frequency,and the magnitude was 0 at resonance frequency.Both the quadrature and phase signals can be used to lock resonance frequency and realize measurement of magnetic field.