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A Le Floch

Publications and source records attributed to A Le Floch.

7 recordsLinked to original sources
PubMed2006

A dipole interaction model for magnetochiral birefringence.

We have developed a classical model to investigate the magnetochiral birefringence of an isotropic chiral medium submitted to a longitudinal magnetic field. This model, which is an extension of the atom dipole interaction model, yields direct calculations from the polarizabilities and positions of the atoms of the considered molecules. The numerical values obtained for the magnetochiral birefringence, as well as for the optical activity and Faraday rotation, are supported by the previously published experimental results on limonene, proline, and tartaric acid.

Journal Article↗
PubMed2003

Lever-assisted two-noise stochastic resonance.

A critical interplay of two correlated noises in a nonlinear symmetrical two-well potential system is experimentally demonstrated. One state can become completely noise free, leading to an infinite Kramers time. If an independent lever breaks the potential symmetry, stochastic resonance is recovered. In this new regime, we obtain a plateau, i.e., a high signal-to-noise ratio even for vanishing forcing signals.

Models, Theoretical↗
PubMed2001

Stochastic resonances in an optical two-order parameter vectorial system.

We show experimentally that optical two-dimensional systems such as vectorial lasers can exhibit novel stochastic resonances. All optical noise and modulation of this system allows the isolation of so-called inhibitional and rotational stochastic resonances. In particular, incoherent rotational tunneling is shown to be sensitive enough to be also induced by Faraday noise and by quantum noise, i.e., external spontaneous emission.

Journal Article↗
PubMed2001

Rabi-Lorentzian profile of an atomic resonance obtained with Gaussian beams.

We demonstrate that the interaction between atoms and a Gaussian beam changes the Lorentzian resonance into a so-called Rabi-Lorentzian resonance profile. The existence of such profiles is experimentally evidenced in a dark resonance situation for metastable (4) He, in the absence of any external perturbation. A topological mechanism is shown theoretically to account for the measured profiles. We observe a 3% systematic residual with respect to a pure Lorentzian profile, which could play a role in the search of high precision in the measurement of fundamental constants.

Journal Article↗