We propose and demonstrate a type of magneto-optical trap (MOT) for alkaline-earth-metal-like (AEML) atoms where the narrow intercombination ${}^1{S}_0\to {}^3{P}_1$ transition and the broad ${}^1{S}_0\to {}^1{P}_1$ 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 ${}^{174}\mathrm{Yb}$ 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.

• Received 5 January 2015

DOI:https://doi.org/10.1103/PhysRevA.91.053405