Narrow-line Cooling and Determination of Magic Wavelength of Cd

Authors
A. Yamaguchi, M. S. Safronova, K. Gibble, and H. Katori

Abstract
We experimentally and theoretically determine the magic wavelength of the $\left(5s^2\right){1S}_0-\left(5s5p\right)3P_0$ clock transition of $111\mathrm{Cd}$ to be 419.88(14) and 420.1(7) nm. To perform Lamb-Dicke spectroscopy of the clock transition, we use narrow-line laser cooling on the ${1S}_0-{3P}_1$ transition to cool the atoms to $6\mu K$ and load them into an optical lattice. Cadmium is an attractive candidate for optical lattice clocks because it has a small sensitivity to blackbody radiation and its efficient narrow-line cooling mitigates higher order light shifts. We calculate the blackbody shift, including the dynamic correction, to be fractionally $2.83\left(8\right)\times {10}^{-16}$ at 300 K, an order of magnitude smaller than that of Sr and Yb. We also report calculations of the Cd $1P_1$ lifetime and the ground state $C_6$ coefficient.

Physical Review Letters : https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.123.113201