用于全光铯原子磁力仪的激光器稳频技术研究

全光铯原子磁力仪是采用光学的方法实现微弱磁场检测,激光频率稳定性直接影响磁力仪的灵敏度。分析了二向色性原子蒸气激光频率锁定(Dichroic atomic vapor laser lock DAVLL)技术用于稳定激光器频率的原理,及其在全光原子磁力仪中的应用优势,发现通常的二能级原子模型不适用于分析铯原子D2线的稳频。实验测量了不同磁场下铯原子D2线基态Fg=4和Fg=3跃迁的DAVLL光谱,发现16mT是实现DAVLL稳频的最佳磁场;在此磁场附近,基态Fg=4跃迁鉴频曲线零点相对于Fg=4→Fe=5跃迁会产生6MHz/mT的线性频移,基态Fg=3跃迁鉴频曲线零点相对于Fg=3→Fe=4线会产生-9MHz/mT的线性频移。

Study of frequency stabilization of a diode laser at all optical Cs atom magnetometer

Theory of all optical cesium magnetometer is based on the optical testing which can be used in weak magnetic field measurement.The character of laser frequency stabilization would affect the magnetometer sensitivity directly.In this work,the principle of dichroic atomic vapor laser lock(DAVLL) is analyzed and compared with the other frequency stabilization methods.The method basing on traditional two-level atom is not applicable to cesium D2 transitional frequency stabilization.The DAVLL spectra of D2 line from ground states of Fg=4 and Fg=3 transitions at different magnetic field are measured.That the optimum magnetic field is about 16mT for two transitions is found out.The dependence of the frequency shift of the zero point of the frequency discrimination curve on the magnetic field strength is discussed.The result show that the magnetic field would make the zero point from ground state Fg =4 transition shift of 6MHz/mT relative to Fg=4→Fe=5 transition and shift of-9MHz/mT for ground Fg=3 transition relative to Fg=3→Fe=4 transition near the optimum field respectively.