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arXiv · 0802.1585

Experimental Realization of an Optical One-Way Barrier for Neutral Atoms

Jeremy J. Thorn·Elizabeth A. Schoene·Tao Li·Daniel A. Steck
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Abstract

We demonstrate an asymmetric optical potential barrier for ultracold 87 Rb atoms using laser light tuned near the D_2 optical transition. Such a one-way barrier, where atoms impinging on one side are transmitted but reflected from the other, is a realization of Maxwell's demon and has important implications for cooling atoms and molecules not amenable to standard laser-cooling techniques. In our experiment, atoms are confined to a far-detuned dipole trap consisting of a single focused Gaussian beam, which is divided near the focus by the barrier. The one-way barrier consists of two focused laser beams oriented almost normal to the dipole-trap axis. The first beam is tuned to have a red (blue) detuning from the F=1 -> F' (F=2 -> F') hyperfine transitions, and thus presents a barrier only for atoms in the F=2 ground state, while letting F=1 atoms pass. The second beam pumps the atoms to F=2 on the reflecting side of the barrier, thus producing the asymmetry.

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Jeremy J. Thorn, Elizabeth A. Schoene, Tao Li, Daniel A. Steck. 2008-05-24. Experimental Realization of an Optical One-Way Barrier for Neutral Atoms. https://doi.org/10.1103/physrevlett.100.240407

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