A vector atomic magnetometer based on the spin self-sustaining Larmor method

We demonstrate a three-axis atomic magnetometer capable of measuring the magnitude and direction of a magnetic field based on the spin self-sustaining method using a rubidium vapor. Vectorial capability is added by precise compensation in three components of the magnetic field since the Larmor precession frequency is stable and constant in this process. A mean sensitivity of 0.78 pT/ Hz in the measurement of the field magnitude and a sensitivity of 3.5 × 10 - 6 rad/ Hz in the measurement of direction are realized. The coherence lifetime of atomic spins is lengthened to 340 ms and the sensitivity improves with time following a much faster τ - 1 rule which enables the magnetometer to reach the quantum shot noise floor in a much shorter time.