title: Subfemtotesla scalar atomic magnetometry using multipass cells.
abstract: Scalar atomic magnetometers have many attractive features but their sensitivity has been relatively poor. We describe a Rb scalar gradiometer using two multipass optical cells. We use a pump-probe measurement scheme to suppress spin-exchange relaxation and two probe pulses to find the spin precession zero crossing times with a resolution of 1 psec. We realize a magnetic field sensitivity of 0.54 fT/Hz(1/2), which improves by an order of magnitude the best scalar magnetometer sensitivity and exceeds, for example, the quantum limit set by the spin-exchange collisions for a scalar magnetometer with the same measurement volume operating in a continuous regime.
authors.affiliation: Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: D
authors.initials: D
authors.lastname: Sheng
authors.forename: S
authors.initials: S
authors.lastname: Li
authors.forename: N
authors.initials: N
authors.lastname: Dural
authors.forename: M V
authors.initials: MV
authors.lastname: Romalis