Tri-axis optical pumping magnetometer for gradiometric measurement

摘要

A tri-axis vector optically pumped magnetometer comprises a cell (1) filled with an atomic gas subjected to an ambient magnetic field whose projection on three axes of rectangular coordinates defines three components and a photodetector ( 10) arranged to receive a probe beam having passed through the cell. The photodetector (10) comprises a plurality of measurement units arranged in a plane transverse to a direction of propagation of the probe beam, the measurement units each providing a photodetection signal. The magnetometer further comprises a processing unit (6) configured: - to determine, for each measurement unit and from the photodetection signal supplied by the measurement unit, a measurement, associated with the measurement unit, of each the three components of the ambient magnetic field; and - to calculate at least one difference between the measurements, associated with different measurement units, of a component of the magnetic field and to deliver a gradiometric measurement signal comprising the at least one calculated difference. Figure for the abstract: Figure 1