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A: Atomphysik
A 1: Posters Monday (Cluster, Atoms in Fields)
A 1.32: Poster
Montag, 2. April 2001, 12:30–15:00, AT3
Hanle effect in Rydberg atoms — •Igor Ryabtsev and Denis Tretyakov — Institute of Semiconductor Physics, pr.Lavrentyeva 13, 630090 Novosibirsk, Russia
The Hanle effect in ground-state atoms appears in the magnetic field as depolarization of resonant fluorescence at spontaneous transitions from the excited degenerate states, while in a zero magnetic field the fluorescence is completely polarized due to an interference of degenerate Zeeman sublevels. Usually Hanle signals have lorentzian or dispersive shapes with a width determined by the relaxation rate of the excited state.
In the case of microwave transitions between the highly excited Rydberg states an interference of degenerate sublevels in the magnetic field can appear in a different way. Since the spontaneous relaxation of Rydberg states is almost absent, envelope of the Hanle signal is determined by the spectral width of the microwave emission. Quantum beats can also be observed in the signals.
We have studied experimentally the Hanle effect in Rydberg atoms of sodium. An interference signal of the 37P3/2-37S1/2 microwave transition at 70.166 GHz was recorded in the variable magnetic field. When the duration of the microwave pulse was less than 0.5 µs the interference oscillations of the probability were observed at the σ polarization of exciting laser emission. An envelope of the oscillations corresponded to the spectral width of the pulse. At π polarization the oscillations were absent, and the signal had anomalous asymmetrical shape which is not described by theory.
This work was supported by the Russian Foundation for Basic Research Grants Nos. 99-02-17131, 00-02-17924, and 00-02-17993.