title: Laser locking to the 199Hg 1S0-3P0 clock transition with 5.4 × 10(-15)/✓τ fractional frequency instability.
abstract: With 199Hg atoms confined in an optical lattice trap in the Lamb-Dicke regime, we obtain a spectral line at 265.6 nm for which the FWHM is ~15 Hz. Here we lock an ultrastable laser to this ultranarrow 1S0-3P0 clock transition and achieve a fractional frequency instability of 5.4×10(-15)/✓τ for τ ≤ 400 s. The highly stable laser light used for the atom probing is derived from a 1062.6 nm fiber laser locked to an ultrastable optical cavity that exhibits a mean drift rate of -6.0×10(-17) s(-1) (-16.9 mHz s(-1) at 282 THz) over a six month period. A comparison between two such lasers locked to independent optical cavities shows a flicker noise limited fractional frequency instability of 4×10(-16) per cavity.
authors.affiliation: LNE-SYRTE, Observatoire de Paris, CNRS, UPMC, Paris, France. john.mcferran@obspm.fr
authors.forename: J J
authors.initials: JJ
authors.lastname: McFerran
authors.forename: D V
authors.initials: DV
authors.lastname: Magalhães
authors.forename: C
authors.initials: C
authors.lastname: Mandache
authors.forename: J
authors.initials: J
authors.lastname: Millo
authors.forename: W
authors.initials: W
authors.lastname: Zhang
authors.forename: Y
authors.initials: Y
authors.lastname: Le Coq
authors.forename: G
authors.initials: G
authors.lastname: Santarelli
authors.forename: S
authors.initials: S
authors.lastname: Bize