Zero-field magnetometry based on the combination of atomic orientation and alignment

Abstract: Optically pumped magnetometers usually rely on optical pumping using circularly- or linearly-polarized light. We study here zero-field magnetometers pumped with elliptically-polarized light, preparing both atomic orientation and alignment with complementary geometries. We start by extending the "three-step approach" for elliptically-polarized pumping. This allows us studying the Hanle effect in elliptical polarization by comparing the analytical absorption signals with experiments made on helium-4 metastable state. We then study parametric resonance magnetometers based on elliptical polarization by using the dressed-atom formalism with one and two radio-frequency fields. The results show a good agreement with the experimental measurements and open interesting perspectives for magnetometry where symmetry breaking by pumping light is mitigated.