Vector measurements using a pulsed, optically pumped atomic magnetometer
| DWPI Title: Measuring ambient magnetic field with atomic magnetometer, involves applying magnetic field to probe light beam to rotate polarization vector of atomic population along probe axis |
| Abstract: An atomic magnetometer, and a method for using same is disclosed. The method for measuring an ambient magnetic field uses an atomic magnetometer that has a probe light beam with a probe axis that probes a polarization vector of an atomic population confined within a vapor cell. The method employs one or more measurement cycles. In each measurement cycle, the polarization vector is prepared in an initial state via an optical pumping pulse. The vapor cell is then subjected to the ambient magnetic field, which results in rotation of the polarization vector by Larmor precession. Within the measurement cycle, at a point in time after the polarization vector has been prepared in the initial state, the ambient magnetic field rotates the direction of the polarization vector, and at least one measurement is made of a projection of the Larmor-rotated polarization vector onto the probe axis during or after application of a magnetic waveform. |
| Use: Method for measuring ambient magnetic field with atomic magnetometer for magnetoencephalography applications. Uses include but are not limited to ordinance detection applications, geophysical mapping applications, navigation applications and detection of bio-magnetic fields associated with heart and brain activity applications. |
| Advantage: The method obviates any need for orthogonality between the pump and probe light beam axes and allows any or all vector components of the field to be measured. |
| Novelty: The method involves preparing the polarization vector P in an initial state with the optical pump pulse, applying a magnetic waveform along at least an axis orthogonal to at least one of the pump axis or the probe axis to the vapor cell (12) so as to rotate the direction of the polarization vector P, the magnetic waveform including at least one of a magnetic π/2 pulse or a magnetic π pulse, subjecting the vapor cell to the ambient magnetic field B, whereby the polarization vector P is rotated by Larmor precession; and making at least one projection measurement of a projection of the thus Larmor-rotated polarization vector P onto the probe axis, each of the at least one projection measurements being made during or after applying the magnetic waveform. |
| Filed: 7/28/2022 |
| Application Number: US17875500A |
| Tech ID: SD 15595.1 |
| This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy/National Nuclear Security Administration. The Government has certain rights in the invention. |
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