A $^{3}$He-$^{129}$Xe co-magnetometer probed by a Rb magnetometer with Ramsey-pulse technique

We report the recent progress in development of a new kind of co-magnetometer, benifiting from both the long spin coherence time of a noble gas and a highly sensitive alkali metal magnetometer. Due to the Fermi-contact interaction between alkali metal electron spin and noble gas nuclear spin the effective magnetization of the noble gas is enhanced by a factor of 6 to 600, allowing near quantum-limited detection of nuclear spins. Collisions between polarized alkali atoms and noble gas also introduce a large shift to the nuclear spin precession frequency. We reduce this effect by using Ramsey pulse techniques to measure the noble gas spin precession frequency ``in the dark'' by turning off the pumping laser between Ramsey pulses. A furthur reduction of the back-hyperpolarization from the noble gas can be achieved by controlling the cell temperature on short time scale. We showed that a $^{3}$He-$^{129}$Xe Ramsey co-magnetometer is effective in cancelling fluctuations of external magnetic fields and gradients and developed cells with sufficient $^{129}$Xe $T_2$ time without surface coatings. The new co-magnetometer has potential applications for many precision measurements, such as searches for spin-gravity couplings, electric dipole moments, and nuclear spin gyroscopes.