Two optically pumped atomic magnetometer geometries, with sub-fT/Hz sensitivity for radio frequencies, are contrasted: one with a probe beam of high power and few passes through the atoms, the other with low power and many passes. Theoretical noise sensitivity for these conditions is modeled and compared to experimental values, with the latter geometry achieving a sensitivity of 0.19 ± 0.02 fT/Hz. Further, a general approach for choosing probe parameters to optimize sensitivity is given. With the use of a λ/2 wave plate, both systems are also configured to act as an intrinsic gradiometer, enabling the rejection of common-mode interference. Common-mode interference is reduced by over 50 dB in both geometries.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics