An Optically Pumped MagnetometerWorking in the Light-Shift Dispersed Mz Mode
in: Sensors (2017)
We present an optically pumped magnetometer working in a new operational mode – the light-shift dispersed Mz (LSD-Mz) mode. It is realized combining various features; (1) high power off-resonant optical pumping, (2) Mz configuration, where pumping light and magnetic field of interest are oriented parallel to each other, (3) use of small alkali metal vapor cells of identical properties in integrated array structures, where two such cells are pumped by circularly polarized light of opposite helicity, and (4) subtraction of the Mz signals of these two cells. The LSD- Mz magnetometer's performance depends on the inherent and very complex interplay of input parameters. In order to find the configuration of optimal magnetometer resolution, a sensitivity analysis of the input parameters by means of latin hypercube sampling was carried out. The resulting datasets of the multi-dimensional parameter space exploration were assessed by a subsequent physically reasonable interpretation. Finally, the best shot-noise limited magnetic field resolution was determined within that parameter space. As the result, using two 50 mm3 integrated vapor cells a magnetic field resolution below 10 fT/√Hz at Earth’s magnetic field strength is possible.