Advances in optically pumped He4 magnetometers : Resonance and nonresonance techniques

2014 Samples of optically pumped 23S1 helium atoms are currently studied in our laboratory for use in advanced magnetometer applications. The results of recent investigations of the effect of pumping beam orientation with respect to the observed magnetic field are presented in this paper. The orientation dependence of the amplitude and frequency of the magnetic resonance signal observed by optical techniques has been measured. These results are used to predict the effect of orientation on scalar field change measurements. The experiments are theoretically interpreted by taking into account the contribution of the individual magnetic resonances and the perturbation of magnetic states by real and virtual transitions. The orientation dependence of the optical pumping process is used to construct a nonresonance magnetometer (no magnetic resonance) suitable for measuring vector interplanetary and laboratory fields in the range 2014 200 03B3 ~ H ~ 200 03B3. Several new optical pumping components which have contribued to the advancement of helium magnetometers are discussed. REVUE DE PHYSIQUE APPLIQUÉE TOME 5, FÉVRIER 1970, PAGE