Propagation of light through small clouds of cold interacting atoms

Abstract

We demonstrate experimentally that a cloud of cold atoms with a size comparable to the wavelength of light can induce large group delays on a laser pulse when the laser is tightly focused on it and is close to an atomic resonance. Delays as large as -10 ns are observed, corresponding to "superluminal" propagation with negative group velocities as low as -300 m/s. Strikingly, this large delay is associated with a moderate extinction owing to the very small size of the cloud and to the light-induced interactions between atoms. It implies that a large phase shift is imprinted on the continuous laser beam, and opens interesting perspectives for applications to quantum technologies.

arXiv comment5 pages, 3 figures Supplemental Material : 2 pages, 2 Figures

References in corpus (12)

• Coherent scattering of near-resonant light by a Dense Microscopic Cold Atomic cloud
• Metamaterial transparency induced by cooperative electromagnetic interactions
• Observation of the Nonlinear Phase Shift Due to Single Post-Selected Photons
• Diffraction limited optics for single atom manipulation
• Maximal refraction and superluminal propagation in a gaseous nanolayer
• Phase shift of a weak coherent beam induced by a single atom
• Interfacing light and single atoms with a lens
• Controlling the phase of a light beam with a single molecule
• Evaporative cooling of a small number of atoms in a single-beam microscopic dipole trap
• Direct measurement of the Wigner time-delay for the scattering of light by a single atom
• Sub-Poissonian atom number fluctuations using light-assisted collisions
• Controllable optical phase shift over one radian from a single isolated atom

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• On-resonance material fast light
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• Metalens formed by structured arrays of atomic emitters