Search

Alkali metal-noble gas comagnetometers operated in the regime of spin-exchange relaxation-free (SERF) have been widely used in fundamental physics tests and rotation sensing as gyroscope. Spin-exchange relaxation is an important systematic bias of the comagnetometer, which could limit sensitivity significantly. However, the suppression effect of the spin-exchange relaxation has not been examined quantitatively so far. Herein, we systematically investigate the relaxation of the alkali metal atoms and find that the spin-exchange relaxation is not completely eliminated under the normal operating condition of the K-Rb-21Ne comagnetometer. In addition to the optical pumping rate, the spin-exchange relaxation still plays a dominant role in the broadening of electron Zeeman resonances due to the large electron magnetic field. This is the first demonstration that the alkali metal atoms are operated in the near-SERF regime in the alkali metal-noble gas comagnetometer with a large election magnetic field, which will shed light on the way to reduce the relaxation of the alkali metal atoms and enhance the sensitivity of the comagnetometer. [ABSTRACT FROM AUTHOR]

We propose a novel method for measuring relaxation rates and Fermi-contact fields of the electron and nuclear spin ensembles rapidly and synchronously in spin-exchange relaxation-free (SERF) atomic comagnetometers based on the transient response. The transient response model of the comagnetometer is established by solving a set of Bloch equations. The decay rates and oscillation frequencies of the transient response as functions of the longitudinal magnetic field are investigated theoretically and experimentally. The total relaxation rate of the nuclear spin ensemble is obtained from its decay rate. A linear model is presented with a detailed mathematical derivation based on the decay rates and oscillation frequencies of the spin ensembles. The Fermi-contact fields of the spin ensembles and the slowing-down factor are extracted from the slope and intercept of the linear model. The total relaxation rate of the electron spins is obtained from the decay rates of the spin ensembles and the measured slowing-down factor. The validity of this method is further checked by the magnetic resonance (MR) method from a perspective of the electron resonance linewidth. Identification of these systematic parameters paves the way for operating the comagnetometers efficiently as well as the practical applications of the comagnetometers. [ABSTRACT FROM AUTHOR]