Origin of elevated fluorescence near scan position (1,6) in raster imaging

Ascertain whether the higher fluorescence signal observed near laser scan position (1,6) in the raster scan and rescan of the barium deposit arises from weak excitation of a Ba atom located just outside the scanned area.

Background

During raster-scanned fluorescence imaging of Ba in SXe, the authors report a distinct single-atom candidate that bleaches, alongside a persistent elevated signal at a specific scan coordinate.

It remains unresolved whether this elevated signal corresponds to excitation of a nearby atom beyond the scan boundary or is due to another cause, which affects interpretation of scan features and atom counting.

References

It is not clear whether or not the higher signal around laser position (1,6) in scan (b) and rescan (c) of Fig. \ref{fig:scan1} is from weak excitation of another Ba atom that was just outside the scan area.

— Imaging of single barium atoms in a second matrix site in solid xenon for barium tagging in a $^{136}$Xe double beta decay experiment (2407.00285 - Yvaine et al., 29 Jun 2024) in Results