title: Progress at NIST toward absolute frequency standards using stored ions.
abstract: Experiments directed toward the realization of frequency standards of high accuracy using stored ions are briefly summarized. In one experiment, an RF oscillator is locked to a nuclear spin-flip hyperfine transition (frequency approximately 3.03x10(8) Hz) in (9 )Be(+) ions that are stored in a Penning trap and sympathetically laser-cooled. Stability is better than 3x10(-12)tau(-(1/2)) and uncertainty in Doppler shifts is estimated to be less than 5x10(-15). In a second experiment, a stable laser is used to probe an electric quadrupole transition (frequency approximately 1.07x10(15) Hz) in a single laser-cooled (199)Hg(+) ion stored in a Paul trap. The measured Q value of this transition is approximately 10(13). Future possible experiments are discussed.
authors.affiliation: Nat. Inst. of Stand. and Technol., Boulder, CO.
authors.forename: D J
authors.initials: DJ
authors.lastname: Wineland
authors.forename: J C
authors.initials: JC
authors.lastname: Bergquist
authors.forename: J J
authors.initials: JJ
authors.lastname: Bollinger
authors.forename: W M
authors.initials: WM
authors.lastname: Itano
authors.forename: D J
authors.initials: DJ
authors.lastname: Heinzen
authors.forename: S L
authors.initials: SL
authors.lastname: Gilbert
authors.forename: C H
authors.initials: CH
authors.lastname: Manney
authors.forename: M G
authors.initials: MG
authors.lastname: Raizen