Helium-3 nuclear-spin oscillator for detection of exotic spin couplings

We report on a helium-3 nuclear-spin oscillator that uses a feedback mechanism to self oscillate in the presence of a leading magnetic field. Hybrid pumping of Rb atoms was used to polarize potassium and helium-3 spins in a vapor cell through spin-exchange collisions. The nuclear spins were tipped to start their precession about the leading field. The precession was detected via optical rotation of light detuned from the D1 transition in potassium. This signal was fed back to magnetic field coils surrounding the cell to sustain the oscillation of the helium-3 spins. We investigated the sensitivity of this system to the measurement of exotic spin couplings for potential application to the Global Network of Optical Magnetometers for Exotic physics (GNOME).