Measurement of the van der Waals force using reflection of cold atoms from magnetic thin-film atom mirrorsA. K. Mohapatra and C. S. Unnikrishnan
Fundamental Interactions Lab (Gravitation Group) Tata Institute of Fundamental Research Homi Bhabha Road, Mumbai-400 005, India
received 23 September 2005; accepted in final form 24 January 2006
published online 8 February 2006
We report on a measurement of the van der Waals interaction between rubidium atoms in the ground state and a metallic surface, employing a new method involving reflection of laser-cooled atoms from magnetic thin-film atom mirrors. We made use of the fact that the typical distance from which atoms reflect from thin-film magnetic mirrors is of the order of the magnetic domain size and the thickness of the thin film. The modification of the reflectivity of cold atoms from cobalt thin-film magnetic mirrors, with thickness in the range of , due to the competition between the attractive atom-surface interaction and the repulsive magnetic interaction enabled the measurement of the van der Waals force in the range 20- with an uncertainty of 15%. The measured value agrees well with recent theoretical estimates.
34.50.Dy - Interaction of atoms and molecules with surfaces; photon and electron emission; neutralization of ions.
03.75.Be - Atom and neutron optics.
32.80.Pj - Optical cooling of atoms; trapping.
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