1202.2182 (D. B. Tretyakov et al.)

Effect of photoions on the line shapes of the Förster resonance and
microwave transitions in cold rubidium Rydberg atoms    [PDF]

D. B. Tretyakov, I. I. Beterov, V. M. Entin, E. A. Yakshina, I. I. Ryabtsev, S. F. Dyubko, E. A. Alekseev, N. L. Pogrebnyak, N. N. Bezuglov, E. Arimondo

Experiments on the spectroscopy of the F\"orster resonance Rb(37P)+Rb(37P) ->
Rb(37S)+Rb(38S) and microwave transitions nP -> n'S, n'D between Rydberg states
of cold Rb atoms in a magneto-optical trap have been performed. Under ordinary
conditions, all spectra exhibited a 2-3 MHz line width independently of the
interaction time of atoms with each other or with microwave radiation, although
the ultimate resonance width should be defined by the inverse interaction time.
Analysis of the experimental conditions has shown that the main source of the
line broadening was the inhomogeneous electric field of cold photoions appeared
at the excitation of initial Rydberg nP states by broadband pulsed laser
radiation. Using an additional pulse of the electric field, which rapidly
removed the photoions after the laser pulse, lead to a substantial narrowing of
the microwave and F\"orster resonances. An analysis of various sources of the
line broadening in cold Rydberg atoms has been conducted.

View original: http://arxiv.org/abs/1202.2182