Exploiting the two-dimensional magneto-optical trapping of Hg199 for a mercury optical lattice clock

Abstract

Two-dimensional magneto-optical trapping (2D-MOT) is an efficient tool for generating a high flux of precooled atoms. A 2D-MOT for mercury (Hg) is so far missing despite the potential of this atomic species in several areas. Here, we present the characterization of a 2D-MOT for Hg enabled by addressing the ${}^{1}{S}_{0}$- ${}^{3}{P}_{1}$ laser cooling transition at 254 nm. The laser source based on an ytterbium-doped fiber amplifier has low-frequency noise and high reliability. Parameters affecting the efficiency of the 2D-MOT are studied, i.e., optical trapping power, push beam power, cooling laser frequency detuning, and magnetic-field gradient. When used with a Hg optical lattice clock, the 2D-MOT increases by a factor of 4.5, the rate of preparation of the atomic samples, yielding an improved clock short term stability of $6.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}16}$ at 1 s.