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Q: Quantenoptik

Q 22: Poster: Quantum Effects

Q 22.5: Poster

Thursday, April 5, 2001, 12:30–15:00, AT2

Coherent Population Trapping Involving Rydberg and Autoionizing States in Xenon — •Michael Stellpflug, Thomas Halfmann, Knut Böhmer, and Klaas Bergmann — Fachbereich Physik, Universität Kaiserslautern, D-67663 Kaiserslautern

Spectroscopy techniques relying on the interaction of strong, coherent radiation with matter permit the generation of pronounced dark resonances with an improved signal-to-noise-ratio compared to methods involving incoherent processes. We investigated Rydberg and autoionizing states in Xenon by coherent population trapping and dark resonances. A weak two-photon coupling is induced between the ground state of Xenon and an intermediate state. The strong coupling between the intermediate and the investigated excited states, generated by a second radiation field, suppresses population transfer to the intermediate state. The effect of coherent population trapping was found to be very robust with respect to the chosen atomic levels and laser-intensity fluctuations. It could even be implemented with lasers of poor coherence properties. We demonstrated the reliability of the technique with a laser system, providing laser-pulses of transform-limited bandwidth as well as with a conventional broadband laser system. The depth of the resonances clearly exceeded the value of 50 %, expected for incoherent interaction.