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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 > Archives > Control of Interactions between Ultracold Atoms using Frequency-Chirped Light

Control of Interactions between Ultracold Atoms using Frequency-Chirped Light

Mercredi 27 avril 2011 à 11h30 en salle de réunion de l’IFRAF, au 45 rue d’Ulm, Paris : Séminaire du professeur Phil Gould de l’Université du Connecticut.

Résumé :

We use frequency-chirped laser light on the nanosecond time scale to control interactions between trapped ultracold Rb atoms. Pulses of chirped light from a diode laser system excite atom pairs to a long-range attractive molecular potential, leading to a measurable loss from the trap. Matching the time scale of the dynamics to that of the chirp gives the possibility of controlling the collisions.

As one example, we compare loss rates for positive and negative linear chirps and observe rather different behaviors. Depending on the center detuning of the chirp, the loss rate for the negative chirp can be either enhanced or suppressed relative to that for the positive chirp.

We attribute this to the multiple, in some cases coherent, interactions between the colliding pair and the chirped light as the negative chirp “follows” the resonance condition of the converging atom pair. We have attempted to extend this control by “shaping” chirps to match the collisional dynamics. We have also observed the formation of ground-state molecules using photoassociation with chirped light.


Le professeur Phil Gould est actuellement visiteur au laboratoire Aimé Cotton.


Post-scriptum :

La salle de réunion de l’IFRAF est au 4e étage du bâtiment Rataud au fond de la cour Pasteur à l’Ecole normale supérieure 45 rue d’Ulm 75005 PARIS.