title: High bandwidth atomic magnetometery with continuous quantum nondemolition measurements.
abstract: We describe an experimental study of spin-projection noise in a high sensitivity alkali-metal magnetometer. We demonstrate a fourfold improvement in the measurement bandwidth of the magnetometer using continuous quantum nondemolition measurements. Operating in the scalar mode with a measurement volume of 2 cm3 we achieve magnetic field sensitivity of 22 fT/Hz(1/2) and a bandwidth of 1.9 kHz with a spin polarization of only 1%. Our experimental arrangement is naturally backaction evading and can be used to realize sub-fT sensitivity with a highly polarized spin-squeezed atomic vapor.
authors.affiliation: Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: V
authors.initials: V
authors.lastname: Shah
authors.forename: G
authors.initials: G
authors.lastname: Vasilakis
authors.forename: M V
authors.initials: MV
authors.lastname: Romalis