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Claude Cohen Tannoudji

Prix Nobel en 1997 pour le ralentissement et le piégeage des atomes par la lumière laser.

Ses travaux sont à la source des recherches actuelles de l'IFRAF.




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Accueil du site > Séminaires > IFRAF > Three magics to hold an atom without perturbation

Three magics to hold an atom without perturbation

Mercredi 1er juillet 2009, 14h, Salle de réunion de l’IFRAF, ENS, 45 rue d’Ulm, Paris.

Séminaire exceptionnel du professeur D. Cho (Department of Physics, Korea University, Seoul 136-713, Korea)


Trapped atoms with long interrogation time provide excellent sample for both spectroscopy and quantum information processing (QIP). Potential well of a trap, however, perturbs internal state of atoms as well as holding them. Even in an optical trap, which is least perturbative among various traps, systematic shift and in homogeneous broadening of a transition seriously limit its utility as a tool in spectroscopy and QIP. We will report some of the tricks developed to overcome this difficulty.

For a transition in an optical frequency domain, magic wavelength using three-level system has been demonstrated for cesium and ytterbium atoms. We have proposed magic power for a pulsed optical trap, which can result in a perturbation-free spectroscopy of a transition in an optical frequency domain. The idea is applicable to a general two-level system and we carried out a proof-of-principle experiment using cesium atoms. For a hyperfine transition of a ground-state alkali metal atoms, dual beam optical trap and spin-echo have been tried to overcome the inhomogeneous broadening with a limited success. Recently we proposed the idea of magic polarization, where difference in the scalar polarizabilities of the two hyperfine levels is compensated by the vector polarizabilities.

With a proper polarization of the trapping beam, the vector term can be tuned to eliminate the systematic shift and the inhomogeneous broadening of a microwave transition. We will report our progress in the magic polarization experiment using lithium atoms.

Post-scriptum :

Department of Physics
Korea University, Seoul 136-713