Dynamics of a Spin-Exchange Relaxation-Free Comagnetometer for Rotation Sensing

We investigate the dynamics of the spin-exchange relaxation-free (SERF) comagnetometer for rotation sensing. The transient and steady-state models of the rotation response are established by solving a set of Bloch equations. The transient responses of the comagnetometer with inertial rotation input and magnetic field input are compared. The effects of the pump-laser power density on the transient response are studied and the results indicate that the transient response reaches the fastest when the pumping rate equals the product of the gyromagnetic ratio and polarization field factor of the electron spins. The measuring range of the comagnetometer is investigated by experiment and simulation, which suggests that the measuring range can be improved by increasing the relaxation rates of the electron spins and nuclear spins and the ratio of the Fermi-contact field of the electron spins to that of the nuclear spins. The theory and method presented here pave the way for the practical application of SERF comagnetometers for rotation sensing.