The Experts below are selected from a list of 19557 Experts worldwide ranked by ideXlab platform

Jacques Albert - One of the best experts on this subject based on the ideXlab platform.

  • Evanescent wave on the Gold-Coating tilt fiber grating surface and its sensing applications
    2015 14th International Conference on Optical Communications and Networks (ICOCN), 2015
    Co-Authors: Youqing Wang, Changyu Shen, Fengying Shentu, Jacques Albert
    Abstract:

    The scatterings of P and S-polarized evanescent wave on the surface of a tilted fiber Bragg grating (TFBG) with a 50 nm thick Gold Coating were investigated experimentally by observing radiation patterns from discontinuities in the Coating. The scattering intensity for P-polarized light is larger than for S-polarized light when the evanescent wave propagates from the Coating towards the discontinuity. Using the characteristics of the polarization of the evanescent wave, the in-line polarimeter and twist sensors were designed.

  • plasmon resonances in Gold coated tilted fiber bragg gratings
    Optics Letters, 2007
    Co-Authors: Yanina Shevchenko, Jacques Albert
    Abstract:

    The transmission spectrum of fiber Bragg gratings with gratings planes tilted at a small angle (2°-10°) relative to the fiber axis shows a large number of narrowband cladding mode resonances within a 100 nm wide spectrum. When a Gold Coating with a thickness between 10 and 30 nm is deposited on the fiber, the transmission spectrum shows anomalous features for values of the outside medium refractive index between 1.4211 and 1.4499. These features are shown to correspond to the excitation of surface plasmon resonances at the external surface of the Gold film.

Yanina Shevchenko - One of the best experts on this subject based on the ideXlab platform.

  • plasmon resonances in Gold coated tilted fiber bragg gratings
    Optics Letters, 2007
    Co-Authors: Yanina Shevchenko, Jacques Albert
    Abstract:

    The transmission spectrum of fiber Bragg gratings with gratings planes tilted at a small angle (2°-10°) relative to the fiber axis shows a large number of narrowband cladding mode resonances within a 100 nm wide spectrum. When a Gold Coating with a thickness between 10 and 30 nm is deposited on the fiber, the transmission spectrum shows anomalous features for values of the outside medium refractive index between 1.4211 and 1.4499. These features are shown to correspond to the excitation of surface plasmon resonances at the external surface of the Gold film.

D. Vouagner - One of the best experts on this subject based on the ideXlab platform.

  • Surface-enhanced Raman scattering of amorphous TiO2 thin films by Gold nanostructures: Revealing first layer effect with thickness variation
    Journal of Applied Physics, 2013
    Co-Authors: S. Degioanni, A.-m. Jurdyc, François Bessueille, J. Coulm, Bernard Champagnon, D. Vouagner
    Abstract:

    In this paper, amorphous titanium dioxide (TiO2) thin films have been deposited on a commercially available Klarite substrate using the sol-gel process to produce surface-enhanced Raman scattering (SERS). The substrate consists of square arrays of micrometer-sized pyramidal pits in silicon with a Gold Coating. Several thin TiO2 layers have been deposited on the surface to study the influence of film thickness. Ultimately, we obtained information on SERS of an amorphous TiO2 layer by Gold nanostructures, whose range is less than a few nanometers. Mechanisms responsible for the enhancement are the product of concomitant chemical and electromagnetic effects with an important contribution from plasmon-induced charge transfer

Thorsten Reineke - One of the best experts on this subject based on the ideXlab platform.

  • effects of Gold Coating of coronary stents on neointimal proliferation following stent implantation
    American Journal of Cardiology, 2002
    Co-Authors: Urgen Vom J Dahl, Philipp K Haager, Eberhard Grube, Michael Gross, C Beythien, Eckhard P Kromer, N Cattelaens, Christian W Hamm, Rainer Hoffmann, Thorsten Reineke
    Abstract:

    Abstract Experimental studies suggest a reduced neointimal tissue proliferation in vascular stainless steel stents coated with Gold. This prospective multicenter trial evaluated the impact of Gold Coating on neointimal tissue proliferation in patients undergoing elective stent implantation. The primary end point was the in-stent tissue proliferation measured by intravascular ultrasound at 6 months comparing stents of identical design with or without Gold Coating (Inflow). Two hundred four patients were randomized to receive uncoated (group A, n=101) or coated (group B, n=103) stents. Baseline parameters did not differ between the groups. Stent length and balloon size were comparable, whereas inflation pressure was slightly higher in group A (14 ± 3 vs 13 ± 3 atm, p=0.013). Procedural success was similar (A, 97%; B, 96%). The acute angiographic result was better for group B (remaining stenosis 4 ± 12% vs 10 ± 11%, p=0.002). Six-month examinations revealed more neointimal proliferation in group B. By ultrasound, the neointimal volume within the stent was 47 ± 25 versus 41 ± 23 mm 3 (p = 0.04), with a ratio of neointimal volume-to-stent volume of 0.45 ± 0.12 versus 0.40 ± 0.12 (p = 0.003). The angiographic minimal luminal diameter was smaller in group B (1.47 ± 0.57 vs 1.69 ± 0.70 mm, p=0.04), with a higher late luminal loss of 1.17 ± 0.51 versus 0.82 ± 0.56 mm (p = 0.001). Thus, Gold Coating of the tested stent type resulted in more neointimal tissue proliferation.

Nadjib Semmar - One of the best experts on this subject based on the ideXlab platform.

  • Thermal behaviour of electric connector Coating irradiated by a laser beam
    Microelectronics Journal, 2002
    Co-Authors: Nadjib Semmar, Cecile Georges, Chantal Boulmer-leborgne
    Abstract:

    Abstract In this work, one dimension unsteady heat problem is resolved to simulate laser treatment of an electric connector Coating. The electrochemical Gold Coating processing is not sufficient to limit the corrosion inside the connector. Thus an excimer laser beam interacts with the surface to recover a regular smooth surface by melting. The laser fluence must be adjusted to ensure the partial melting of the Gold Coating without its evaporation. The modelling of heat diffusion allows calculating the optimal fluence range (laser energy). Typically, for 0.75 μm surface Coating on a multilayer metallic substrate, the laser fluence is ranging from 390 to 550 mJ/cm 2 . The temperature profile is also plotted to describe the Coating thermal field. Finally, the effect of the heat density (laser intensity) time distribution in the temperature profile and the melting depth is discussed.

  • laser treatment for corrosion prevention of electrical contact Gold Coating
    Applied Surface Science, 2002
    Co-Authors: Nadjib Semmar, H Sanchez, C Perrin, Cecile Georges, Chantal Boulmerleborgne, D Simon
    Abstract:

    Abstract The materials used in electrical contact applications are constituted of a copper alloy (brass or bronze) electroplated with two Coatings, a nickel layer (diffusion barrier) and a Gold layer (corrosion barrier). There are some pores in the nickel and Gold layers leading to corrosion of the underlying layers. To modify the Gold Coating microstructure, a laser surface treatment has been undertaken. An excimer laser is used firstly because the photon absorption coefficient is larger in UV range and secondly because the laser beam homogeneity is available for a surface treatment. The purpose of this surface treatment is to suppress the porosity of the Gold layer, which is responsible of the corrosion pits, and to smooth the surface as the roughness prevents a correct electrical contact. The effects of the laser treatment are studied according to different surface parameters (roughness of the substrate, thickness of the two successive Coatings, a nickel layer and a Gold layer). A numerical code is used to simulate the influence of the laser beam parameter on the surface melting. Tests of corrosion are carried out in the humid synthetic air containing low contents of pollutants (NO 2 , SO 2 and Cl 2 ). The techniques used to control these effects are optical microscopy and scanning electron microscopy (SEM).

  • Thermal behaviour of electric connector Coating irradiated by a laser beam
    Microelectronics Journal, 2002
    Co-Authors: Nadjib Semmar, Cédric Georges, Chantal Boulmer-leborgne
    Abstract:

    In this work, one dimension unsteady heat problem is resolved to simulate laser treatment of an electric connector Coating. The electrochemical Gold Coating processing is not sufficient to limit the corrosion inside the connector. Thus an excimer laser beam interacts with the surface to recover a regular smooth surface by melting. The laser fluence must be adjusted to ensure the partial melting of the Gold Coating without its evaporation. The modelling of heat diffusion allows calculating the optimal fluence range (laser energy). Typically, for 0.75μm surface Coating on a multilayer metallic substrate, the laser fluence is ranging from 390 to 550mJ/cm2. The temperature profile is also plotted to describe the Coating thermal field. Finally, the effect of the heat density (laser intensity) time distribution in the temperature profile and the melting depth is discussed. © 2002 Elsevier Science Ltd. All rights reserved.

  • Laser treatment for corrosion prevention of electrical contact Gold Coating
    Applied Surface Science, 2002
    Co-Authors: Cédric Georges, Nadjib Semmar, H Sanchez, C Perrin, Chantal Boulmer-leborgne, D Simon
    Abstract:

    The materials used in electrical contact applications are constituted of a copper alloy (brass or bronze) electroplated with two Coatings, a nickel layer (diffusion barrier) and a Gold layer (corrosion barrier). There are some pores in the nickel and Gold layers leading to corrosion of the underlying layers. To modify the Gold Coating microstructure, a laser surface treatment has been undertaken. An excimer laser is used firstly because the photon absorption coefficient is larger in UV range and secondly because the laser beam homogeneity is available for a surface treatment. The purpose of this surface treatment is to suppress the porosity of the Gold layer, which is responsible of the corrosion pits, and to smooth the surface as the roughness prevents a correct electrical contact. The effects of the laser treatment are studied according to different surface parameters (roughness of the substrate, thickness of the two successive Coatings, a nickel layer and a Gold layer). A numerical code is used to simulate the influence of the laser beam parameter on the surface melting. Tests of corrosion are carried out in the humid synthetic air containing low contents of pollutants (NO2, SO2and Cl2). The techniques used to control these effects are optical microscopy and scanning electron microscopy (SEM). © 2002 Elsevier Science B.V. All rights reserved.