Core-shell magneto-optical trap for alkaline-earth-metal-like atoms

We propose and demonstrate a type of magneto-optical trap (MOT) for alkaline-earth-metal-like ( AEML) atoms where the narrow intercombination S-1(0) -> P-3(1) transition and the broad S-1(0) -> P-1(1) transition are spatially arranged into a core-shell configuration. Our scheme resolves the main limitations of previously adopted MOT schemes for AEML atoms, leading to significant increases in both the loading rate and the steady-state atom number. We apply this scheme to our experimental setup with Yb-174 atoms and observe more than two orders of magnitude improvement in the loading rate and tenfold improvement in the steady-state atom number compared to a conventional intercombination MOT scheme. This technique could be readily extended to other AEML atoms to increase the statistical sensitivity of many different types of precision experiments.