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Accueil > Événements > Séminaires 2013

Manipulation of cold molecular ensembles

Nicolas Vanhaecke

Fritz-Haber-Institut der Max-Planck-Gesellschaft

Faradayweg 4-6, D-14195 Berlin

Laboratoire Aimé Cotton

CNRS/Université Paris-Sud/ENS Cachan, 91405 Orsay, France

The achievements and prospects opened by atoms in the cold and ultracold regimes cover an impressive range of topics : from precision measurements for fundamental physics, metrology, mesoscopic physics and quantum information to applied physics, such as atomic clocks or ultracold ion beams. Cold molecules are expected to reveal even richer physics than cold atoms, since molecules exhibit a rich rotational and vibrational structure and can also possess additional properties, such as a permanent electric dipole moment or chirality [1].
A prominent, versatile method to produce cold molecules relies on the supersonic expansion of a seeded molecular gas, followed by a deceleration of the molecules of the so-formed beam. In this presentation I will outline the operation principle of the various components, which are used in our laboratories to manipulate the motion of the molecules in the beam. The Stark deceleration technique slows down polar molecules with time-dependent electric fields [2], whereas the Zeeman deceleration addresses paramagnetic atoms and molecules [3]. I will also report on the recent, experimental realization of a microwave decelerator for neutral polar molecules, suitable to decelerate and focus molecules in their absolute ground state [5].
In the second part of my talk, I will report on a direct method to accurately measure the density of a Rydberg gas, which we experimentally demonstrate in a supersonic atomic beam. The method gives direct access to the gas density, and requires evaluating neither the atom number nor the volume of the gas. Indeed, two-body information is extracted from controlled dipole-dipole-interaction induced Landau-Zener transitions in pairs of Rydberg atoms in a time-dependent electric field [6].
Finally, I will discuss future possible developments of this field, especially along the research line aiming at ultracold temperatures. Arguably manipulation of cold molecules in the gas phase could be pursued by combining existing methods with techniques and concepts borrowed from interface science and plasmonics.

[1] Topical issue, Chemical Reviews 112 (9) 4801-5072, 2012.

[2] H.L. Bethlem, G. Berden, and G. Meijer. Phys. Rev. Lett. 83, 1558, 1999.

[3] N. Vanhaecke, U. Meier, M. Andrist, B.H. Meier, and F. Merkt. Phys. Rev. A 75, 031402, 2007.

[4] S. Merz, N. Vanhaecke,W. Jäger, M. Schnell, and G. Meijer. Phys. Rev. A, 85:063411, 2012.

[5] N. Saquet, A. Cournol, J. Beugnon, J. Robert, P. Pillet, and N. Vanhaecke. Phys. Rev. Lett. 104, 133003, 2010.