title: Shot-noise-limited monitoring and phase locking of the motion of a single trapped ion.
abstract: We perform a high-resolution real-time readout of the motion of a single trapped and laser-cooled Ba+ ion. By using an interferometric setup, we demonstrate a shot-noise-limited measurement of thermal oscillations with a resolution of 4 times the standard quantum limit. We apply the real-time monitoring for phase control of the ion motion through a feedback loop, suppressing the photon recoil-induced phase diffusion. Because of the spectral narrowing in the phase-locked mode, the coherent ion oscillation is measured with a resolution of about 0.3 times the standard quantum limit.
authors.affiliation: Physikalisches Institut, Karlsruher Institut für Technologie, D-76128 Karlsruhe, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Bushev
authors.forename: G
authors.initials: G
authors.lastname: Hétet
authors.forename: L
authors.initials: L
authors.lastname: Slodička
authors.forename: D
authors.initials: D
authors.lastname: Rotter
authors.forename: M A
authors.initials: MA
authors.lastname: Wilson
authors.forename: F
authors.initials: F
authors.lastname: Schmidt-Kaler
authors.forename: J
authors.initials: J
authors.lastname: Eschner
authors.forename: R
authors.initials: R
authors.lastname: Blatt