Sensitive and Stable Atomic Vector Magnetometer to Detect Weak Fields Using Two Orthogonal Multipass Cavities

Abstract

This paper presents a compact low-temperature atomic vector magnetometer for weak-field measurements, using an atomic cell containing two orthogonal multipass cavities. At the working temperature of $75{\phantom{\rule{0.1em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$, the magnetic field sensitivities at all three axes are better than $45\phantom{\rule{0.2em}{0ex}}\mathrm{fT}\phantom{\rule{0.2em}{0ex}}{\mathrm{Hz}}^{\ensuremath{-}1/2}$ at 10 Hz limited by photon noise, and $85\phantom{\rule{0.2em}{0ex}}\mathrm{fT}\phantom{\rule{0.2em}{0ex}}{\mathrm{Hz}}^{\ensuremath{-}1/2}$ at 0.1 Hz. This sensor also shows measurement stabilities better than 1.5 pT at three axes for an integration time of ${10}^{4}\phantom{\rule{0.2em}{0ex}}\mathrm{s}$, even with the laser frequency unlocked. The sensor response to a rotation is demonstrated, which is also developed to measure the effective gyromagnetic ratio of atoms in this sensor when the bias field is nulled. This magnetometer makes an important step towards long-term stable measurements and calibrations of ultralow fields.