The atomic beam crosses the cavity mode.

The preparation of the atoms in the excited state, before they enter the cavity, seems to work. Efforts are under way to laser-cool further the atomic velocity distribution, in directions transverse to the atomic beam flow.

Fluorescence of 88Sr atoms, excited by a beam coupled to the cavity mode. (This signal is not collected on the narrow transition, but on the broader 1S0 -> 1P1 line). From this signal, we estimate that the atom number inside the mode will be above threshold for superradiance.