title: Doppler-free spectroscopy of the 1S0-3P0 optical clock transition in laser-cooled fermionic isotopes of neutral mercury.
abstract: We report direct laser spectroscopy of the 1S0-3P0 transition at 265.6 nm in fermionic isotopes of neutral mercury in a magneto-optical trap. Measurements of the frequency against the LNE-SYRTE primary reference using an optical frequency comb yield 1 128 575 290 808.4+/-5.6 kHz in 199Hg and 1 128 569 561 139.6+/-5.3 kHz in 201Hg. The uncertainty, allowed by the observation of the Doppler-free recoil doublet, is 4 orders of magnitude lower than previous indirect determinations. Mercury is a promising candidate for future optical lattice clocks due to its low sensitivity to blackbody radiation.
authors.affiliation: LNE-SYRTE, Observatoire de Paris, 75014 Paris, France.
authors.forename: M
authors.initials: M
authors.lastname: Petersen
authors.forename: R
authors.initials: R
authors.lastname: Chicireanu
authors.forename: S T
authors.initials: ST
authors.lastname: Dawkins
authors.forename: D V
authors.initials: DV
authors.lastname: Magalhães
authors.forename: C
authors.initials: C
authors.lastname: Mandache
authors.forename: Y
authors.initials: Y
authors.lastname: Le Coq
authors.forename: A
authors.initials: A
authors.lastname: Clairon
authors.forename: S
authors.initials: S
authors.lastname: Bize