Faraday Rotation with Single Nuclear Spin Qubit in a High-Finesse Optical Cavity

Understand

When an off-resonant light field is coupled with atomic spins, its polarization can rotate depending on the direction of the spins via a Faraday rotation which has been used for monitoring and controlling the atomic spins.

• We observed Faraday rotation by an angle of more than 10 degrees for a single 1/2 nuclear spin of 171Yb atom in a high-finesse optical cavity.
• By employing the coupling between the single nuclear spin and a photon, we have also demonstrated that the spin can be projected or weakly measured through the projection of the transmitted single ancillary photon.