US 12,436,208 B2
Methodology to measure sensitive magnetic fields through coupled pump/probe fields
Michael A. Slocum, Dayton, OH (US); and Robert G. Bedford, Beavercreek, OH (US)
Assigned to United States of America as represented by the Secretary of the Air Force, Wright-Patterson AFB, OH (US)
Filed by Government of the United States, as represented by the Secretary of the Air Force, Wright-Patterson AFB, OH (US)
Filed on May 17, 2023, as Appl. No. 18/319,269.
Claims priority of provisional application 63/342,698, filed on May 17, 2022.
Prior Publication US 2023/0393221 A1, Dec. 7, 2023
Int. Cl. G01R 33/032 (2006.01)
CPC G01R 33/032 (2013.01) 18 Claims
OG exemplary drawing
 
1. A magnetometer, comprising:
a resonant cavity comprising a first mirror positioned at a first end of the resonant cavity and a second mirror positioned at a second end of the resonant cavity, the second end opposing the first end;
a nitrogen vacancy (NV) diamond material positioned in the resonant cavity between the first and second mirrors;
an excitation beam source configured to direct an excitation beam into the resonant cavity, the excitation beam configured to excite the NV diamond material from a ground state to an excited state;
a probe beam source configured to direct a probe beam into the resonant cavity, the probe beam configured to probe an intermediate singlet state of the NV diamond material;
a radio frequency (RF) source configured to emit RF radiation with a photon energy resonant with transition energy between ground and excited state of the NV diamond material;
a photodetector, configured to measure probe beam power; and
a first controller, configured to reduce probe beam power fluctuations by correspondingly adapting a control signal associated with at least one of probe beam power and excitation beam power;
wherein a strength and direction of a magnetic field proximate the NV diamond material may be determined using probe beam measurements,
the first controller is configured to adapt at least one of probe beam power and excitation beam power in accordance with a proportional-integral-derivative (PID) control loop, and
the first controller PID control loop is further responsive to changes of the RF radiation power level.