Optically pumped, radio-frequency atomic magnetometry with feedback stabilization
| DWPI Title: Magnetometer for detecting a communication signal, comprises atomic vapor cell having longitudinal propagation axis for pump beam of light, three-axis set of field coils arranged to apply magnetic field to vapor cell, photodetector arranged to receive probe light that has passed through vapor cell |
| Abstract: An optically pumped, atomic magnetometer incorporates a feedback system for stabilizing the magnetic bias field and suppressing unwanted background fields. The magnetic bias field is applied to a vapor cell containing host atoms of two different species, each of which resonates at a different Larmor frequency when both are subjected to the same magnetic bias field. One species provides the feedback for stabilizing the bias field, thereby creating a stabilizing magnetometer portion that nulls out the unwanted background fields. The other species provides magnetic field detection or signal reception on a radio communication frequency of interest, thereby creating a signal magnetometer portion that permits detection of the signal at the radio communication frequency. |
| Use: Magnetometer for detecting a communication signal is used in a radio-frequency receiver. |
| Advantage: The magnetometer incorporates a feedback system for stabilizing the magnetic bias field and suppressing unwanted background fields so that the device can be operated outside a magnetic shield. It allows for a very compact design. All the information for the feedback comes from one source at one concentrated location. The magnetometer design can operate without magnetic shielding but can still exhibit extremely high sensitivity. |
| Novelty: Magnetometer comprises an atomic vapor cell having a longitudinal propagation axis for a pump beam of light, here denominated the z-axis. The three-axis set of field coils arranged to apply a magnetic field to the vapor cell. The photodetector arranged to receive probe light that has passed through the vapor cell and to provide, in response to it, an output signal that indicates a polarization state of the received probe light. The driving circuitry for driving the field coils. The demodulator circuitry configured to demodulate a signal stream derived from the photodetector output signal with respect to a longitudinal demodulation frequency fLS, thus to produce a first one of the error signals, and to demodulate a signal stream derived from the photodetector output signal with respect to a transverse demodulation frequency fTS, thus to produce a second one of the error signals. The communication signal output port and a signal path to it for the photodetector output signal. |
| Filed: 12/14/2021 |
| Application Number: US17550503A |
| Tech ID: SD 15652.0 |
| 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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