All-optical production and trapping of metastable noble gas atoms down to the single atom regime (Vol. 46 No. 1)

Fluorescence of up to four trapped Kr-84 atoms as a function of time.

The determination of isotope ratios of noble gases has many applications e.g. in physics, nuclear arms control and earth sciences. In many cases, low concentrations of wanted noble gas isotopes (e.g. Kr and Ar in air or groundwater samples) make single atom detection necessary to achieve an adequate precision of measurement. As an important step into this direction, we demonstrate operation of an Atom Trap Trace Analysis (ATTA) setup based on a magneto-optical trap (MOT) for metastable Kr atoms excited by all-optical means. Compared to other state-of-the-art techniques for preparing metastable noble gas atoms, all-optical production is capable of overcoming limitations regarding minimal sample volume and avoiding cross-contamination. In addition, it allows for a compact and reliable setup. We identify optimal parameters of our experimental setup by employing the most abundant isotope Kr-84, and demonstrate single atom detection within a 3D MOT.

M. Kohler et al., “All-optical production and trapping of metastable noble-gas atoms down to the single-atom regime”, EPL 108, 13001 (2014)