Time filter

Source Type

Clerc M.G.,University of Chile | Garcia-Nustes M.A.,University of Chile | Zarate Y.,University of Chile | Coulibaly S.,CNRS Laser Physics Laboratory
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2013

Parametrically driven extended systems exhibit dissipative localized states. Analytical solutions of these states are characterized by a uniform phase and a bell-shaped modulus. Recently, a type of dissipative localized state with a nonuniform phase structure has been reported: the phase shielding solitons. Using the parametrically driven and damped nonlinear Schrödinger equation, we investigate the main properties of this kind of solution in one and two dimensions and develop an analytical description for its structure and dynamics. Numerical simulations are consistent with our analytical results, showing good agreement. A numerical exploration conducted in an anisotropic ferromagnetic system in one and two dimensions indicates the presence of phase shielding solitons. The structure of these dissipative solitons is well described also by our analytical results. The presence of corrective higher-order terms is relevant in the description of the observed phase dynamical behavior. © 2013 American Physical Society.


Wolf P.,CNRS Time Space Reference Systems | Blanchet L.,CNRS Paris Institute of Astrophysics | Borde C.J.,CNRS Time Space Reference Systems | Borde C.J.,CNRS Laser Physics Laboratory | And 3 more authors.
Classical and Quantum Gravity | Year: 2011

Atom interferometers allow the measurement of the acceleration of freely falling atoms with respect to an experimental platform at rest on Earth's surface. Such experiments have been used to test the universality of free fall by comparing the acceleration of the atoms to that of a classical freely falling object. In a recent paper, Müller et al (2010 Nature 463 926-9) argued that atom interferometers also provide a very accurate test of the gravitational redshift (or universality of clock rates). Considering the atom as a clock operating at the Compton frequency associated with the rest mass, they claimed that the interferometer measures the gravitational redshift between the atom-clocks in the two paths of the interferometer at different values of gravitational potentials. In this paper, we analyze this claim in the frame of general relativity and of different alternative theories. We show that the difference of 'Compton phases' between the two paths of the interferometer is actually zero in a large class of theories, including general relativity, all metric theories of gravity, most non-metric theories and most theoretical frameworks used to interpret the violations of the equivalence principle. Therefore, in most plausible theoretical frameworks, there is no redshift effect and atom interferometers only test the universality of free fall. We also show that frameworks in which atom interferometers would test the redshift pose serious problems, such as (i) violation of the Schiff conjecture, (ii) violation of the Feynman path integral formulation of quantum mechanics and of the principle of least action for matter waves, (iii) violation of energy conservation, and more generally (iv) violation of the particle-wave duality in quantum mechanics. Standard quantum mechanics is no longer valid in such frameworks, so that a consistent interpretation of the experiment would require an alternative formulation of quantum mechanics. As such an alternative has not been proposed to date, we conclude that the interpretation of atom interferometers as testing the gravitational redshift at the Compton frequency is unsound. © 2011 IOP Publishing Ltd.


Laliotis A.,University of Paris 13 | Laliotis A.,CNRS Laser Physics Laboratory | Ducloy M.,University of Paris 13 | Ducloy M.,CNRS Laser Physics Laboratory | Ducloy M.,Nanyang Technological University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2015

We take a closer look at the fundamental Casimir-Polder (CP) interaction between quantum particles and dispersive dielectric surfaces with surface polariton or plasmon resonances. Linear response theory shows that in the near-field, van der Waals regime the free-energy shift of a particle contains a thermal component that depends exclusively on the excitation of the evanescent surface polariton (plasmon or phonon) modes. Our work makes evident the link between particle surface interaction and near-field thermal emission and demonstrates how this can be used to engineer Casimir-Polder forces. We also examine how the exotic effects of surface waves are washed out as the distance from the surface increases. In the case of molecules or excited-state atoms, far-field approximations result in a classical dipole-dipole interaction which depends on the surface reflectivity and the mean number of photons at the frequency of the atomic or molecular transition. Finally we present numerical results for the CP interaction between Cs atoms and various dielectric surfaces with a single polariton resonance and discuss the implications of temperature and retardation effects for specific spectroscopic experiments. ©2015 American Physical Society.


Szunerits S.,Lille University of Science and Technology | Maalouli N.,Lille University of Science and Technology | Maalouli N.,CNRS Laser Physics Laboratory | Wijaya E.,CNRS Institute of Electronics, Microelectronics and Nanotechnology | And 2 more authors.
Analytical and Bioanalytical Chemistry | Year: 2013

Surface plasmon resonance (SPR) is a powerful technique for measurement of biomolecular interactions in real-time in a label-free environment. One of the most common techniques for plasmon excitation is the Kretschmann configuration, and numerous studies of ligand-analyte interactions have been performed on surfaces functionalized with a variety of biomolecules, for example DNA, RNA, glycans, proteins, and peptides. A significant limitation of SPR is that the substrate must be a thin metal film. Post-coating of the metal thin film with a thin dielectric top layer has been reported to enhance the performance of the SPR sensor, but is highly dependent on the thickness of the upper layer and its dielectric constant. Graphene is a single-atom thin planar sheet of sp2 carbon atoms perfectly arranged in a honeycomb lattice. Graphene and graphene oxide are good supports for biomolecules because of their large surface area and rich π conjugation structure, making them suitable dielectric top layers for SPR sensing. In this paper, we review some of the key issues in the development of graphene-based SPR chips. The actual challenges of using these interfaces for studying biomolecular interactions will be discussed and the first examples of the use of graphene-on-metal SPR interfaces for biological sensing will be presented. © 2013 Springer-Verlag Berlin Heidelberg.


Ballin P.,CNRS Laser Physics Laboratory | Moufarej E.,CNRS Laser Physics Laboratory | Maurin I.,CNRS Laser Physics Laboratory | Laliotis A.,CNRS Laser Physics Laboratory | Bloch D.,University of Paris 13
Applied Physics Letters | Year: 2013

We confine a Cs thermal vapor in the interstitial regions of a glass opal. We perform linear reflection spectroscopy on a cell whose window is covered with a thin film (10 or 20 layers) of ∼1000 nm (or 400 nm) diameter glass spheres and observe sub-Doppler structures in the optical spectrum for a large range of oblique incidences. This original feature associated with the inner (3-dimensional) confinement of the vapor in the interstitial regions of the opal evokes a Dicke narrowing. We finally consider possible micron-size references for optical frequency clocks based on weak, hard to saturate, molecular lines. © 2013 AIP Publishing LLC.


Bloch D.,CNRS Laser Physics Laboratory | Bloch D.,University of Paris 13
Physical Review Letters | Year: 2015

A Comment on the Letter by K.A. Whittaker et al., Phys. Rev. Lett. 112, 253201 (2014).PRLTAO0031-900710.1103/PhysRevLett.112.253201 © Published by the American Physical Society 2015.


Buldyreva J.,University of Franche Comte | Margules L.,CNRS Laser Physics Laboratory | Motiyenko R.A.,CNRS Laser Physics Laboratory | Rohart F.,CNRS Laser Physics Laboratory
Journal of Quantitative Spectroscopy and Radiative Transfer | Year: 2013

Relaxation parameters for K-components (K≤6) of six J→J+1 rotational transitions (J=6, 10, 17, 22, 31 and 33) of CH3 35Cl perturbed by O2 are measured at room temperature with Voigt, speed-dependent Voigt and Galatry profiles in order to probe the speed-dependence effects. With respect to the previous study of CH3 35Cl-N2 system [Guinet et al., J Quant Spectrosc Radiat Transfer 2012;113:1113], higher active-gas pressures are reached, providing better signal-to-noise ratios, and the exact expression of the Beer-Lambert law is introduced in the fitting procedure, leading, among other advantages, to much more realistic low-pressure results. The broadening parameters of the considered lines are also computed by a semi-classical method for various relative velocities of colliders and the powers characterizing the dependence of the collisional cross-sections on relative speeds are deduced as functions of the rotational numbers J and K. Additional calculations performed with the Maxwell-Boltzmann distribution of velocities show no significant difference with the earlier results [Buldyreva et al., Phys Chem Chem Phys 2011;13:20326] obtained within the mean thermal velocity approximation. Weighted sums of the presently measured Voigt-profile O2-broadening parameters and of the previously published N2-broadening ones are calculated to yield experimental air-broadening coefficients for spectroscopic databases. © 2013 Elsevier Ltd.


Hydrogen-broadening coefficients of methyl chloride rotational lines J=6→7, 10→11, 17→18, 22→23 and 31→32 at 296K are measured as functions of the quantum number K using a sensitive frequency-modulation technique. As expected for this light perturber, the observed line shapes are well described by Voigt profile model. A clear dependence of the collisional broadening on K is observed for most transitions. From a detailed study of the K-components of the transition J=6→7 situated at 186GHz no variation of the broadening of the hyperfine components related to 35Cl quadrupole is stated. Given the absence of refined ab initio computed potential energy surfaces and the impracticality of quantum-mechanical calculations for the considered molecular system, theoretical values of these broadening coefficients are estimated by a semi-classical approach with exact trajectories and a model interaction potential including both long-range and short-range (atom-atom) interactions of the active molecule rigorously treated as a symmetric top. It is shown that the short-range forces yield important contributions to the collisional line width for all values of the rotational quantum numbers J and K. Various models are also tested for the isotropic part of the interaction potential which governs the relative translational motion. It is demonstrated that for the very light perturbing molecule H2 the calculated line widths, practically independent from the rotational quantum number J (for K≤J), are particularly sensitive to the position and slope of the repulsive wall. Modifications required in the semi-classical formalism for a correct application of the cumulant expansion are also tested and it is stated that no difference is observed for the CH 3Cl-H 2 system characterised by quite weak interactions. © 2012 Taylor & Francis.


Constantin F.L.,CNRS Laser Physics Laboratory
EFTF 2012 - 2012 European Frequency and Time Forum, Proceedings | Year: 2012

The measurement of the frequency difference of rovibrational transitions from two different molecules is suggested to test the variation of the electron-to-proton mass-ratio μ. The frequency of rovibrational transitions is sensitive to μ. Small frequency splittings reached between the transitions from two isotopomers allow an enhancement relative to the variation of μ. © 2012 IEEE.


Ould-Agha Y.,CNRS Laser Physics Laboratory | Betourne A.,CNRS Laser Physics Laboratory | Vanvincq O.,CNRS Laser Physics Laboratory | Bouwmans G.,CNRS Laser Physics Laboratory | Quiquempois Y.,CNRS Laser Physics Laboratory
Optics Express | Year: 2012

Hybrid Photonic Crystal Fibers with a first ring of high index inclusions are studied and compared to both standard air-hole fibers and all solid photonic bandgap fibers. In such new fibers a bandgap-like core mode exists over a wide spectral range and exhibits confinement losses ten orders of magnitude smaller than those of the corresponding all-solid fiber. This particular fiber supports also a core mode guided by modified total internal reflection at long enough wavelengths. The origin and properties of these two kinds of modes are discussed in details. Such a design can also act as a mode filter (as compared to the standard air-hole structure) and could also be used to ease phase matching conditions for nonlinear optics. © 2012 Optical Society of America.

Loading CNRS Laser Physics Laboratory collaborators
Loading CNRS Laser Physics Laboratory collaborators