From Single Atoms to Engineered “Super-Atoms”: Interfacing Photons and Atoms in Free Space

Figure 5

Relevant electronic levels of atomic . (a) An absorption of two resonant photons at 272 nm resonantly brings one of the electrons of neutral into the continuum. Alternatively the resonant photoionization takes place after the first absorption of a 272 nm photon, a decay to the state , and the following absorption of a second photon. Note that other levels can be alternatively used in a neutral for the resonant photoionization [44]. (b) The corresponding level structure of the resulting atomic ion with one valence electron.

(a)

(b)