Patterns are ubiquitous in nature and have been extensively studied in biology, chemistry and physics including optics. We report here on experiments where pattern formation occurs in a cloud of laser cooled atoms. We identify three different mechanisms allowing spatial patterns to spontaneously emerge in either the atomic density, the excited...
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January 11, 2018 (v1)Conference paperUploaded on: December 4, 2022
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2005 (v1)Journal article
We experimentally study radiation trapping of near-resonant light in a cloud of laser-cooled rubidium atoms. Unlike in most previous studies, dealing with hot vapors, collisional broadening is here negligible and Doppler broadening due to the residual atomic velocity is narrower than the homogeneous broadening. This is an interesting new...
Uploaded on: December 3, 2022 -
December 5, 2005 (v1)Publication
We have observed self-sustained radial oscillations in a large magneto-optical trap (MOT), containing up to $10^{10}$ Rb$^{85}$ atoms. This instability is due to the competition between the confining force of the MOT and the repulsive interaction associated with multiple scattering of light inside the cold atomic cloud. A simple analytical...
Uploaded on: December 3, 2022 -
May 2014 (v1)Journal article
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October 3, 2014 (v1)Publication
We investigate the scaling behavior of a very large magneto-optical trap (VLMOT) containing up to $1.4 \times 10^{11}$ Rb$^{87}$ atoms. By varying the diameter of the trapping beams, we are able to change the number of trapped atoms by more than 5 orders of magnitude. We then study the scaling laws of the loading and size of the VLMOT, and...
Uploaded on: March 25, 2023 -
July 7, 2006 (v1)Journal article
By using the coherent backscattering interference effect, we investigate experimentally and theoretically how coherent transport of light inside a cold atomic vapour is affected by the residual motion of atomic scatterers. As the temperature of the atomic cloud increases, the interference contrast dramatically decreases emphazising the role of...
Uploaded on: December 4, 2022 -
November 1, 2011 (v1)Journal article
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Uploaded on: December 3, 2022 -
2004 (v1)Conference paper
Propagation in a random medium is often described by a random walk and a diffusion coefficient. However in the mesoscopic regime, where wave properties cannot be neglected, interferences alter the diffusion process leading in extreme situations to strong (Anderson) localisation. The recent observation of coherent backscattering of light by...
Uploaded on: December 3, 2022 -
January 9, 2023 (v1)Journal article
A large cloud of 87 Rb atoms confined in a magneto-optical trap exhibits, in a certain regime of parameters, spatiotemporal instabilities with a dynamics resembling that of a turbulent fluid. We apply the methods of turbulence theory based on structure function analysis to extract scaling exponents which are compared to known turbulent regimes....
Uploaded on: November 25, 2023 -
September 2010 (v1)Journal article
We demonstrate a technique based on invariants of motion for a time-dependent Hamiltonian, allowing a fast transition to a final state identical in theory to that obtained through a perfectly adiabatic transformation. This method is experimentally applied to the fast decompression of an ultracold cloud of 87 Rb atoms held in a harmonic magnetic...
Uploaded on: December 3, 2022 -
2004 (v1)Journal article
We investigate some signatures of multiple scattering of light in a vapor of laser-cooled rubidium atoms. This sample presents several unusual properties when compared to classical samples i.e. white paper or suspensions of dielectric particles: a very strong resonance, an internal structure of the atomic scatterer, and a spherically symmetric...
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2022 (v1)Journal article
Considering light-mediated long-range interactions between cold atoms in a magneto-optical trap (MOT), we present numerical evidence of a nonequilibrium steady state (NESS) for sufficiently large number of atoms (>108). This state manifests itself as the appearance of an anisotropic distribution of velocity when a MOT approaches the threshold...
Uploaded on: November 25, 2023 -
2004 (v1)Journal article
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...
Uploaded on: December 4, 2022 -
October 11, 2018 (v1)Journal article
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Uploaded on: December 4, 2022 -
2018 (v1)Journal article
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May 19, 2021 (v1)Journal article
We propose a new approach, based on the Hanbury Brown and Twiss intensity interferometry, to transform a Cherenkov telescope to its equivalent optical telescope. We show that, based on the use of photonics components borrowed from quantum-optical applications, we can recover spatial details of the observed source down to the diffraction limit...
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June 10, 2018 (v1)Conference paper
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February 21, 2023 (v1)Journal article
Abstract We report on observations of the extended environment of the bright Be star γ -Cas performed using intensity interferometry measurements within its H α emission line. These observations were performed using a modified version of the I2C intensity interferometry instrument installed onto the 1.54 m MéO optical metrology telescope and a...
Uploaded on: October 13, 2023 -
September 13, 2022 (v1)Publication
The Siegert relation relates field and intensity temporal correlations. After a historical review of the Siegert relation and the Hanbury Brown and Twiss effect, we discuss the validity of this relation in two different domains. We first show that this relation can be used in astrophysics to determine the fundamental parameters of stars, and...
Uploaded on: December 3, 2022 -
July 17, 2022 (v1)Conference paper
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Uploaded on: October 15, 2023