Vector magnetometer based on the effect of coherent population trapping

The method is presented for converting a coherent population trapping (CPT) atomic clock into a CPT vector (compass-) magnetometer without mechanically moving parts through a relatively simple add-on. The system of 3D Helmholtz coils was used for compensation of the external magnetic field, allowing measurement of both strength and direction of a magnetic field at the sensitivity level of sub-nT/Hz1/2 within a 10-Hz bandwidth. Angular resolution of the developed vector magnetometer amounts to about 10-2 degrees.