Magnetic Field Enhanced Coherence Length in Cold Atomic Gases

Olivier Sigwarth (1) , Guillaume Labeyrie (2) , Thibaut Jonckheere (1) , Dominique Delande (1) , Robin Kaiser (2) , Christian Miniatura (2)

1 LKB (Jussieu) - Laboratoire Kastler Brossel
2 INLN - Institut Non Linéaire de Nice Sophia-Antipolis

We study the effect of an external magnetic field on coherent backscattering of light from a cool rubidium vapor. We observe that the backscattering enhancement factor can be {\it increased} with $B$. This surprising behavior shows that the coherence length of the system can be increased by applying a magnetic field, in sharp contrast with ususal situations. This is mainly due to the lifting of the degeneracy between Zeeman sublevels. We find good agreement between our experimental data and a full Monte-Carlosimulation, taking into account the magneto-optical effects and the geometry of the atomic cloud.

Domaines: Systèmes mésoscopiques et effet Hall quantique [cond-mat.mes-hall]; Physique Atomique [physics.atom-ph]

Olivier Sigwarth, Guillaume Labeyrie, Thibaut Jonckheere, Dominique Delande, Robin Kaiser, et al.. Magnetic Field Enhanced Coherence Length in Cold Atomic Gases. Physical Review Letters, 2004, 93, pp.143906. ⟨hal-00001057v2⟩