Fast extraction of the electron spin-relaxation rate in the SERF magnetometer from a transient response

The magnitude of the electron spin-relaxation rate R rel of the atomic ensemble directly affects the sensitivity of the spin-exchange relaxation-free (SERF) atomic magnetometer (AM). The rapid and in-situ characterization of R rel is of great importance. In this work, a fast extraction method of R rel is proposed with a measurement period shorten to 0.5 s, merely detecting the transient response of SERF AM to a transverse DC excitation magnetic field after switching off the pump beam. In contrast to the conventional methods based on the measurement of the magnetic resonance linewidth, this method circumvents the involvement of optical pumping rate, and enables monitoring R rel under arbitrary polarization, which is expected to improve the authenticity of R rel measurement in a more convenient way.