title: High-accuracy optical clock based on the octupole transition in 171Yb+.
abstract: We experimentally investigate an optical frequency standard based on the 467 nm (642 THz) electric-octupole reference transition (2)S(1/2)(F=0)→(2)F(7/2)(F=3) in a single trapped (171)Yb(+) ion. The extraordinary features of this transition result from the long natural lifetime and from the 4f(13)6s(2) configuration of the upper state. The electric-quadrupole moment of the (2)F(7/2) state is measured as -0.041(5)ea(0)(2), where e is the elementary charge and a(0) the Bohr radius. We also obtain information on the differential scalar and tensorial components of the static polarizability and of the probe-light-induced ac Stark shift of the octupole transition. With a real-time extrapolation scheme that eliminates this shift, the unperturbed transition frequency is realized with a fractional uncertainty of 7.1×10(-17). The frequency is measured as 642 121 496 772 645.15(52) Hz.
authors.affiliation: Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany. nils.huntemann@ptb.de
authors.forename: N
authors.initials: N
authors.lastname: Huntemann
authors.forename: M
authors.initials: M
authors.lastname: Okhapkin
authors.forename: B
authors.initials: B
authors.lastname: Lipphardt
authors.forename: S
authors.initials: S
authors.lastname: Weyers
authors.forename: Chr
authors.initials: C
authors.lastname: Tamm
authors.forename: E
authors.initials: E
authors.lastname: Peik