Low and high intensity velocity selective coherent population trapping in a two-level system

David Wilkowski (1) , Maryvonne Chalony (1) , Robin Kaiser (1) , Anders Kastberg (1)

1 INLN - Institut Non Linéaire de Nice Sophia-Antipolis

An experimental investigation is made of sub-recoil cooling by velocity selective coherent population trapping in a two-level system in Sr. The experiment is carried out using the narrow linewidth intercombination line at 689 nm. Here, the ratio between the recoil shift and the linewidth is as high as 0.64. We show that, on top of a broader momentum profile, subrecoil features develop, whose amplitude is strongly dependent on the detuning from resonance. We attribute this structure to a velocity selective coherent population trapping mechanism. We also show that the population trapping phenomenon leads to complex momentum profiles in the case of highly saturated transitions, displaying a multitude of subrecoil features at integer multiples of the recoil momentum.

Mots clés: Atom cooling methods; Mechanical effects of light on atoms

Domaines: Physique Atomique [physics.atom-ph]

David Wilkowski, Maryvonne Chalony, Robin Kaiser, Anders Kastberg. Low and high intensity velocity selective coherent population trapping in a two-level system. EPL - Europhysics Letters, 2009, 86 (5), pp.53001. ⟨hal-00408262⟩