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Personne :
Messaddeq, Younès

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Messaddeq

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Younès

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Université Laval. Département de physique, de génie physique et d'optique

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ncf11860592

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Voici les éléments 1 - 10 sur 13
  • PublicationAccès libre
    Atomic level structure of Ge-Sb-S glasses : chemical short range order and long Sb-S bonds
    (Elsevier Science, 2018-09-28) Pethes, Ildikó; Ari, Julien; Nazabal, Virginie; Messaddeq, Younès; Kaban, Ivan; Darpentigny, Jacques; Welter, Edmund; Gutowski, Olof; Bureau, Bruno; Jóvári, Pál
    The structure of Ge20Sb10S70, Ge23Sb12S65 and Ge26Sb13S61 glasses was investigated by neutron diffraction (ND), X-ray diffraction (XRD), extended X-ray absorption fine structure (EXAFS) measurements at the Ge and Sb K-edges as well as Raman scattering. For each composition, large scale structural models were obtained by fitting simultaneously diffraction and EXAFS data sets in the framework of the reverse Monte Carlo (RMC) simulation technique. Ge and S atoms have 4 and 2 nearest neighbors, respectively. The structure of these glasses can be described by the chemically ordered network model: Ge-S and Sb-S bonds are always preferred. These two bond types adequately describe the structure of the stoichiometric glass while S-S bonds can also be found in the S-rich composition. Raman scattering data show the presence of Ge-Ge, Ge-Sb and Sb-Sb bonds in the S-deficient glass but only Ge-Sb bonds are needed to fit diffraction and EXAFS datasets. A significant part of the Sb-S pairs has 0.3–0.4 Å longer bond distance than the usually accepted covalent bond length (∼2.45 Å). From this observation it was inferred that a part of Sb atoms have more than 3 S neighbors.
  • PublicationAccès libre
    Femtosecond self-reconfiguration of laser-induced plasma patterns in dielectrics
    (American Physical Society, 2018-05-11) Messaddeq, Sandra Helena; Varin, Charles; Déziel, Jean-Luc; Dubé, Louis J.; Messaddeq, Younès
    Laser-induced modification of transparent solids by intense femtosecond laser pulses allows fast integration of nanophotonic and nanofluidic devices with controlled optical properties. Experimental observations suggest that the local and dynamic nature of the interactions between light and the transient plasma plays an important role during fabrication. Current analytical models neglect these aspects and offer limited coverage of nanograting formation on dielectric surfaces. In this paper, we present a self-consistent dynamic treatment of the plasma buildup and its interaction with light within a three-dimensional electromagnetic framework. The main finding of this work is that local light-plasma interactions are responsible for the reorientation of laser-induced periodic plasma patterns with respect to the incident light polarization, when a certain energy density threshold is reached. Plasma reconfiguration occurs within a single laser pulse, on a femtosecond time scale. Moreover, we show that the reconfigured subwavelength plasma structures actually grow into the bulk of the sample, which agrees with the experimental observations of self-organized volume nanogratings. We find that mode coupling of the incident and transversely scattered light with the periodic plasma structures is sufficient to initiate the growth and self-organization of the pattern inside the medium with a characteristic half-wavelength periodicity.
  • PublicationAccès libre
    Analysis of inter-core cross-gain modulation in cladding pumped multi-core fiber amplifiers
    (IEEE Xplore, 2018-11-15) Essiambre, René-Jean.; Chen, Haoshuo; Matte-Breton, Charles; Fontaine, Nicolas K.; LaRochelle, Sophie; Ryf, Roland; Messaddeq, Younès
    We numerically investigate pump-induced gain variations in eight-core fi ber amplifi ers. We compare two fi bers with different erbium profi les by varying input power from -25 dBm to 0 dBm in one or four cores. Inter-core cross-gain modulation is < 0.6 dB.
  • PublicationAccès libre
    The EcoChip : a wireless multi-sensor platform for comprehensive environmental monitoring
    (IEEE, 2018-10-31) Tremblay, Denise; Gosselin, Benoit; Morency, Steeve; Faucher, Félix; Sarrazin, Denis; Moineau, Sylvain; Corbeil, Jacques; Sylvain, Matthieu; Messaddeq, Younès; Allard, Michel; Lehoux, Francis; Bharucha, Eric; Raymond, Frédéric
    This paper presents the EcoChip, a new system based on state-of-the-art electro-chemical impedance (EIS) technologies allowing the growth of single strain organisms isolated from northern habitats. This portable system is a complete and autonomous wireless platform designed to monitor and cultivate microorganisms directly sampled from their natural environment, particularly from harsh northern environments. Using 96-well plates, the EcoChip can be used in the field for realtime monitoring of bacterial growth. Manufactured with highquality electronic components, this new EIS monitoring system is designed to function at a low excitation voltage signal to avoid damaging the cultured cells. The high-precision calibration network leads to high-precision results, even in the most limiting contexts. Luminosity, humidity and temperature can also be monitored with the addition of appropriate sensors. Access to robust data storage systems and power supplies is an obvious limitation for northern research. That is why the EcoChip is equipped with a flash memory that can store data over long periods of time. To resolve the power issue, a low-power microcontroller and a power management unit control and supply all electronic building blocks. Data stored in the EcoChip’s flash memory can be transmitted through a transceiver whenever a receiver is located within the functional transmission range. In this paper, we present the measured performance of the system, along with results from laboratory tests in-vitro and from two field tests. The EcoChip has been utilized to collect bio-environemental data in the field from the northern soils and ecosystems of Kuujjuarapik and Puvirnituq, during two expeditions, in 2017 and 2018, respectively. We show that the EcoChip can effectively carry out EIS analyses over an excitation frequency ranging from 750 Hz to 10 kHz with an accuracy of 2.35%. The overall power consumption of the system was 140.4 mW in normal operating mode and 81 µW in sleep mode. The proper development of the isolated bacteria was confirmed through DNA sequencing, indicating that bacteria thrive in the EcoChip’s culture wells while the growing conditions are successfully gathered and stored.
  • PublicationAccès libre
    Co-doped Dy3+ and Pr3+ Ga5Ge20Sb10S65 fibers for mid-infrared broad emission
    (Optical Society of America, 2018-06-13) Ledemi, Yannick; Starecki, Florent; Ari, Julien; Boussard-Plédel, Catherine; Messaddeq, Younès; Doualan, J. L. (Jean Louis); Braud, Alain; Bureau, Bruno; Nazabal, Virginie
    Rare earth ion doped materials are means to obtain cost-effective infrared light sources, with enough brilliance for applications such as gas sensing. Within a sulfide matrix, the simultaneous luminescence of both Pr3+ and Dy3+ in the Ga5Ge20Sb10S65 glass is reported. The use of these two rare earths is giving rise to a broad continuous luminescence in the 2.2–5.5 µm wavelength range, which could be used as a mid-infrared light source for gas-sensing applications. The demonstration of CO2 and CH4 detection using a fiber drawn from these materials is reported.
  • PublicationAccès libre
    Photonic properties of novel Yb3+ doped germanium-lead oxyfluoride glass-ceramics for laser cooling applications
    (Springer, 2018-08-13) Ledemi, Yannick; Thomas, Jyothis; Messaddeq, Younès; Kummara, Venkata Krishnaiah; Seletskiy, Denis V.; Kashyap, Raman; Maïa, Lauro J. Q.
    In recent years, our research group has developed and studied new rare-earth doped materials for the promising technology of solid-state laser cooling, which is based on anti-stokes fluorescence. To the best of our knowledge, our group is the only one in Canada leading the research into the properties of nanoparticles, glasses and glass-ceramics for optical refrigeration applications. In the present work, optical properties of 50GeO2-30PbF2-18PbO-2YbF3 glass-ceramics for laser cooling are presented and discussed as a function of crystallization temperature. Spectroscopic results show that samples have near infrared photoluminescence emission due to the 2F5/2–2F7/2 Yb3+ transition, centered at ~1016 nm with an excitation wavelength of 920 nm or 1011 nm, and the highest photoluminescence emission efficiency occurs for heat-treatment for 5 h at 350°C. The internal photoluminescence quantum yield varies between 99% and 80%, depending on the temperature of heat-treatment, being the most efficient under 1011 nm excitation. The 2F5/2 lifetime increases from 1.472 to 1.970 ms for heat treatments at 330°C to 350°C, respectively, due to energy trapping and the low phonon energy of the nanocrystals. The sample temperature dependence was measured with a fiber Bragg grating sensor, as a function of input pump laser wavelength and processing temperature. These measurements show that the heating process approaches near zero for an excitation wavelength between 1020 and 1030 nm, which is an indication that phonons are removed effectivelly from the glass-ceramic materials, and they can be used for optical laser cooling applications. On the other hand, the temperature increase as a function of input laser power into samples remains constant between 920 and 980 nm wavelength excitation, a temperature variation of 36 K/W (temperature of 58°C/W) was attained under excitation at 950 nm, showing a possible use for biomedical applications to be explored.1)
  • PublicationAccès libre
    Modeling and characterization of cladding-pumped erbium-ytterbium co-doped fibers for amplification in communication systems
    (Institute of Electrical and Electronics Engineers, 2019-12-20) Essiambre, René-Jean.; Ryf, Roland; Matte-Breton, Charles; Fontaine, Nicolas K.; LaRochelle, Sophie; Messaddeq, Younès; Chen, Haoshuo; Kelly, C.
    Cladding-pumped optical fiber amplifiers are of increased interest in the context of space-division multiplexing but are known to suffer from low power efficiency. In this context, ytterbium (Yb) co-doping can be an attractive solution to improve the performance of erbium (Er) doped fiber amplifiers. We present a detailed direct comparison between Er/Yb-co-doping and Er-doping using numerical simulations validated by experimental results. Two double-cladding fibers, one doped with Er only and the other one co-doped with Er and Yb, were designed, fabricated and characterized. Using the experimentally extracted parameters, we simulate multi-core fiber amplifiers and investigate the interest of Er/Yb-co-doping. We calculate the minimum gain of the amplifiers over a 35-nm spectral window considering various scenarios.
  • PublicationAccès libre
    Flexible trans-jacket inscription of fiber Bragg gratings for directional distributed sensing
    (2019-08-29) Morency, Steeve; Fortier, Richard; Messaddeq, Younès; Bernier, Martin; Trépanier, François; Boilard, Tommy
    An array of 18 FBGs spectrally distributed over 70 nm was written in a polyimide-coated fiber, with a single uniform phase-mask, by applying strain on the fiber prior to exposition. This flexible method will be used to develop directional sensor for distributed sensing based on a hybrid glasspolymer multicore fiber.
  • PublicationAccès libre
    Biopolymer-based membranes associated with osteogenic growth peptide for guided bone regeneration
    (Elsevier, 2018-03-14) Saska, Sybele; Messaddeq, Younès; Pigossi, Suzane C.; Oliveira, Guilherme J P L; Teixeira, Lucas N .; Capela, Marisa V.; Gonçalves, Andreia; De Oliveira, Paulo Tambasco; Ribeiro, S. J. L. (Sidney J. L.); Minarelli Gaspar, Ana Maria; Marchetto, Reinaldo
    Barrier membranes for guided bone regeneration (GBR) mainly promote mechanical maintenance of bone defect space and induce osteopromotion. Additionally, biopolymer-based membranes may provide greater bioactivity and biocompatibility due to their similarity to extracellular matrix (ECM).In this study, biopolymers-based membranes from bacterial cellulose (BC) and collagen (COL) associated with osteogenic growth peptide (OGP(10–14)) were evaluated to determine in vitro osteoinductive potential in early osteogenesis; moreover, histological study was performed to evaluate the BC–COL OGP(10–14) membranes on bone healing after GBR in noncritical defects in rat femur. The results showed that the BC–COL and BC–COL OGP(10–14) membranes promoted cell proliferation and alkaline phosphatase activity in osteoblastic cell cultures. However, ECMmineralization was similar between cultures grown on BC OGP(10–14) and BC–COL OGP(10–14) membranes. In vivo results showed that all the membranes tested, including the peptide-free BC membrane, promoted better bone regeneration than control group. Furthermore, the BC–COL OGP(10–14) membranes induced higher radiographic density in the repaired bone than the other groups at 1, 4 and 16 weeks. Histomorpho-metric analyses revealed that the BC–COL OGP(10–14) induced higher percentage of bone tissue in the repaired area at 2 and 4 weeks than others membranes. In general, these biopolymer-based membranes might be potential candidates for bone regeneration applications.
  • PublicationAccès libre
    Demonstration of an erbium-doped fiber with annular doping for low gain compression in cladding-pumped amplifiers
    (The Optical Society, 2018-10-01) Essiambre, René-Jean.; Chen, Haoshuo; Matte-Breton, Charles; Fontaine, Nicolas K.; Jin, Cang; Ryf, Roland; LaRochelle, Sophie; Messaddeq, Younès; Kelly, C.
    We present the design and characterization of a cladding-pumped amplifier with erbium doping located in an annular region near the core. This erbium-doped fiber is proposed to reduce gain saturation, leading to smaller gain compression when compared to uniform core doping. Through numerical simulations, we first compare the performance of three fibers with different erbium doping profiles in the core or the cladding. When the doped fibers are operated at the optimum length, results show that the smaller overlap of the signal mode field with the annular erbium doping region leads to higher gain and lower saturation of the amplifier. A single-core erbium-doped fiber with an annular doping and a D-shaped cladding was fabricated. Measurements demonstrate less than 4 dB of gain compression over the C-band for input power ranging from −40 dBm to 3 dBm. Small gain compression EDFAs are of interest for applications that require input channel reconfiguration. Higher gain and saturation output power are also key issues in cladding-pumped multi-core amplifiers.