A τ−1 measurement across three orders of magnitude based on an atomic spin precession magnetometer in self-sustaining mode

Abstract

The absolute measurement of magnetic fields can be realized by monitoring the Larmor precession of atomic spins. Yet, this spin-precession magnetometer can only be put into use in weak magnetic fields and the sensitivity is limited by the coherence time beyond which, the uncertainty decreases as τ−1/2 rate. Now we demonstrate that the dynamic range of an atomic spin magnetometer can be extended to geomagnetic field magnitude with τ−1 property maintained based on the the self-sustaining method. A mean sensitivity of 20 pT/Hz and a frequency response bandwidth of 5 kHz are realized in a magnetic field of 10000 nT. More important applications in large magnetic fields can be enabled in virtue of the superiority using this self-sustaining magnetometer.