Patent attributes
In general, techniques of this disclosure are directed to a sensor for measuring an external magnetic field. The sensor an optical cavity, a laser medium which together with the optical cavity has a laser threshold, a laser pump, and a radio-frequency (RF) drive applied to the laser medium, such that the laser threshold varies with a change in the external magnetic field. The RF drive may be applied to the laser medium at or around a particular resonance frequency which varies depending on the external magnetic field, such that depending on the value of the external magnetic field, the RF drive induces transitions between at least two states of the laser medium, each state causing a different laser threshold in an intensity of a laser output. Further, the intensity of the laser output may provide a measurement of the value of the external magnetic field.