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French National Center for Scientific Research, CNRS Le Mans Institute of Molecules and Materials | Date: 2013-10-28

A system for recording a digital hologram of an object comprises: a coherent source intended to illuminate the object and thus produce a wave diffracted by the object; and a digital sensor intended to record the digital hologram of the object. It furthermore comprises a spatial phase modulating assembly able to produce in the plane of the sensor a plurality of duplicates of the wave diffracted by the object, the duplicates being offset from each other but overlapping partially, these duplicates forming on the sensor a digital hologram of the object, this hologram being what is referred to as a self-reference hologram.

Leblanc M.,CNRS Le Mans Institute of Molecules and Materials | Maisonneuve V.,CNRS Le Mans Institute of Molecules and Materials | Tressaud A.,CNRS Laboratory of Condensed Matter Chemistry, Bordeaux
Chemical Reviews | Year: 2015

Most important structural types of transition metal fluorocompounds and fluoride salts are reviewed. Besides solid-state or conventional reactions, several new processes are presented for a controlled elaboration of fluorides, such as subcritical solvothermal conditions, gaseous fluorination, reaction in ionic liquids, and low-temperature fluorine insertion. Because of the importance of inorganic metal fluorides in many innovating processes, the knowledge of their structural characteristics appears to be a decisive tool for getting a better understanding of the relevant parameters controlling their physical chemical properties.

Ruello P.,CNRS Le Mans Institute of Molecules and Materials | Gusev V.E.,CNRS Acoustic Lab of Du Maine University
Ultrasonics | Year: 2015

In this review we address the microscopic mechanisms that are involved in the photogeneration processes of GHz-THz coherent acoustic phonons (CAP) induced by an ultrafast laser pulse. Understanding and describing the underlying physics is necessary indeed for improving the future sources of coherent acoustic phonons useful for the non-destructive testing optoacoustic techniques. Getting more physical insights on these processes also opens new perspectives for the emerging field of the opto-mechanics where lattice motions (surface and/or interfaces ultrafast displacements, nanostructures resonances) are controlled by light. We will then remind the basics of electron-phonon and photon-phonon couplings by discussing the deformation potential mechanism, the thermoelasticity, the inverse piezoelectric effect and the electrostriction in condensed matter. Metals, semiconductors and oxide materials will be discussed. The contribution of all these mechanisms in the photogeneration process of sound will be illustrated over several examples coming from the rich literature. © 2014 Elsevier B.V. All rights reserved.

Galven C.,CNRS Le Mans Institute of Molecules and Materials | Dittmer J.,CNRS Le Mans Institute of Molecules and Materials | Suard E.,Laue Langevin Institute | Le Berre F.,CNRS Le Mans Institute of Molecules and Materials | Crosnier-Lopez M.-P.,CNRS Le Mans Institute of Molecules and Materials
Chemistry of Materials | Year: 2012

We have recently demonstrated the instability of Li 7La 3Sn 2O 12 garnet in humid atmosphere: a spontaneous and reversible ionic exchange Li +/H + occurs rapidly, leading to the protonated garnet Li 7-xH xLa 3Sn 2O 12. In the present article, we show that this instability cannot be generalized to all lithium garnets. We have tested different garnets with various cell parameters, lithium quantity, and lithium distribution and have observed that the Li +/H + exchange feasibility is directly connected to the lithium stoichiometry: if the concentration of Li + ions is greater than what can be accommodated on the tetrahedral site commonly occupied, meaning more than three lithium ions per formula, the garnet is sensitive to humidity. Structures determined by powder neutron diffraction are presented for two exchanged garnets: Li 7-xH xLa 3Sn 2O 12 and Li 5-xH xLa 3Nb 2O 12 obtained from ionic exchange in ethanol and benzoic acid. For the Sn one, the ionic Li +/H + exchange is associated with a transition from a tetragonal (I4 1/acd) to a cubic (Ia3̄d) cell, while for the Nb phase, the use of a noncentrosymmetric space group (I2 13), confirmed by second harmonic generation (SHG) test, is essential to describe the structure. The work is completed by 6Li, 7Li, and 119Sn solid state Nuclear Magnetic Resonance (NMR) of the tin compounds. The impact of the Li +/H + exchange on the dynamics of the lithium ions has been investigated by 7Li relaxation, and the dynamics of protons and lithium ions in the exchanged phase have been compared. © 2012 American Chemical Society.

Szczesniak R.,Czestochowa University of Technology | Szczesniak D.,Jan Dlugosz University in Czestochowa | Szczesniak D.,CNRS Le Mans Institute of Molecules and Materials
Physica Status Solidi (B) Basic Research | Year: 2012

The thermodynamic parameters of the superconducting state in calcium under the pressure of 161GPa have been calculated within the framework of the Eliashberg approach. It has been shown that the value of the Coulomb pseudopotential is high (μ* C=0.24) and the critical temperature (TC=25K) should be determined from the modified Allen-Dynes formula. In addition, it has been found that the basic dimensionless ratios of the thermodynamic parameters significantly diverge from the BCS predictions, and take the following values: (i) The zero-temperature energy gap to the critical temperature (R1≡ 2Δ(0)/kBTC) is equal to 4.01. (ii) The ratio R2≡ (CS(TC) equals 2.17, where CSand CNdenote the specific heats for the superconducting and normal states, respectively. (iii) The quantity R3≡TCCN(TC)/H2 C(0)=0.158, where HCindicates the thermodynamic critical field. Finally, it has been proven that the electron effective mass is large and takes the maximum of 2.32meat TC. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mechri C.,CNRS Le Mans Institute of Molecules and Materials | Ruello P.,CNRS Le Mans Institute of Molecules and Materials | Gusev V.,CNRS Le Mans Institute of Molecules and Materials
New Journal of Physics | Year: 2012

Coherent GHz acoustic phonon dynamics in a tubular nanoporous alumina film is studied with picosecond acoustic methods. This study has allowed the determination of the out-of-plane sound velocity and the effective optical index through a time-resolved Brillouin analysis. Several acoustic eigenmodes of the tubular nanoporous alumina film were detected. These GHz eigenmodes exhibit unusual frequency-dependent long lifetimes. Their strong confinement has been explained by the presence of a thin alumina layer at the film/substrate interface which plays the role of an acoustic mirror. Finally, we show that the optical detection process of these long-living eigenmodes can be either enhanced or reduced to zero following a selection rule. In particular, we demonstrate that detection configurations exist where the coherent acoustic phonon and probe light sensitivity functions are orthogonal, leading to cancellation of the photoelastic light scattering mechanism. This has never been reported so far in the physics of the interaction of coherent acoustic phonons with light. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

Temnov V.V.,CNRS Le Mans Institute of Molecules and Materials
Nature Photonics | Year: 2012

Surface plasmon-polaritons are electromagnetic waves that propagate along metal-dielectric interfaces and exist over a wide range of frequencies. They have become popular research tools owing to their subwavelength confinement and potential ability to perform ultrasensitive optical measurements. Driven by tremendous progress in nanofabrication techniques and ultrafast laser technologies, the applications of surface plasmon-polariton nano-optics extend beyond nanoplasmonics. In this Review, we discuss how the use of hybrid multilayer structures combining different functionalities allows the development of active plasmonic devices and new metrologies. Magneto-plasmonics, acousto-plasmonics and the generation of high-energy photoelectrons using ultrashort surface plasmon-polariton pulses are all examples of how the combination of ideas developed in these individual fields can be used to generate new knowledge, leading to a range of exciting applications in nanophotonics. © 2012 Macmillan Publishers Limited. All rights reserved.

Kovalenko O.,CNRS Le Mans Institute of Molecules and Materials | Pezeril T.,CNRS Le Mans Institute of Molecules and Materials | Temnov V.V.,CNRS Le Mans Institute of Molecules and Materials
Physical Review Letters | Year: 2013

It is shown theoretically that a single acoustic pulse, a few picoseconds long, can reverse magnetization in a magnetostrictive material Terfenol-D. Following giant magnetoelastic changes of free energy density, the magnetization vector is ejected from a local in-plane energy minimum and decays into another minimum. For an acoustic pulse duration significantly shorter than magnetization precession period τac Tprec, the switching threshold is determined by the acoustic pulse area, i.e., pulse integral in the time domain, similar to coherent phenomena in optics. Simulation results are summarized in a magnetoacoustic switching diagram and discussed in the context of all-optical magnetization switching by circularly polarized light pulses. © 2013 American Physical Society.

Kengne-Momo R.P.,CNRS Le Mans Institute of Molecules and Materials
Biointerphases | Year: 2012

A simple electrochemical procedure was used for the synthesis of a polythiophene containing para-benzenesulfonyl chloride groups. The obtained polymer was shown to be very reactive and directly able to covalently bind nucleophile biomolecules. Protein A and a specific antibody were then successively immobilized on the conductive polymer through a covalent bonding of Protein A with the as-prepared linker for bacteria trapping purpose. All reactions were controlled in situ by cyclic voltammetry, quartz crystal microbalance and Raman spectroscopy. The results were compared to those previously obtained on gold surface modified with the same chemical linker. The conductive polymer led to a very high rate of antibody recognition compared to the gold surface and to literature, probably due to a large available surface obtained after polymerization. One example of pathogenic bacteria "Salmonella enterica paratyphi" detection was successfully tested on the substrates. The presented results are promising for the future design of simple and inexpensive immunocapture-based sensors.

Youmbi B.S.,CNRS Le Mans Institute of Molecules and Materials | Calvayrac F.,CNRS Le Mans Institute of Molecules and Materials
Surface Science | Year: 2014

We report on the structure of CoO(001) surface. For DFT + U calculations, in order to reach the ground state, the parameter U is obtained by a self-consistent procedure based on the linear-response approach. After confirmation with respect to the experimental bandgap, the calculated parameter U is 3.7 eV. We show that this value is suitable for a good description of CoO electronic and magnetic properties. Contrary to most surfaces, CoO(001) topmost layers relax outwards with the oxygen ions relaxation height greater than that of cobalt ions, leading the surface to exhibit a small rumpling. This surface appears to be catalytically very favorable due to its low surface energy of 0.8 J/m2. It is also shown that this material exhibits Multiple Quantum-Well behavior and thus could be a good candidate for optoelectronic applications. © 2013 Elsevier B.V.

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