Isotropic and all-optical scalar magnetometer for measuring an ambient magnetic field

Abstract

An optical-pumping magnetometer intended to measure an ambient magnetic field. It comprises: an arrangement for illuminating a cell filled with an atomic gas with a pump beam and an AC Stark effect beam propagating collinearly or almost collinearly in the cell, the pump beam being tuned to an atomic transition line, modulated by a first modulator by way of a first modulation frequency (fm1) and polarised linearly in a polarisation direction that can be turned by a polarisation rotator, the AC Stark effect beam being offset from the atomic transition line, modulated by a second modulator by way of a second modulation frequency (fm2) and polarised circularly, a first control circuit acting on the polarisation rotator in order to keep a constant angle (β) between the polarisation direction of the pump beam and the ambient magnetic field, a second control circuit acting on the first and second modulator in order to keep the first and second modulation frequency at the Larmor frequency of the atomic gas or at one of the harmonics thereof.

Dependencies are inferred from the claim text.