8 research outputs found

    Etude des phenomenes de piegeage en volume et en surface dans une structure photoconductrice de type planar sur GaAs

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    SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

    Optofluidic sensor using two-dimensional photonic crystal waveguides

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    Photonic crystal (PC) waveguide is one class of PC devices that has been demonstrated for RI measurements. In this paper, we have reported a new design of infiltrated optofluidic sensors based on 2D photonic crystal slab with triangular lattice pattern of ring-shaped holes. The properties of the sensor are simulated using the finite-difference time-domain (FDTD) method. The transmission spectra have been measured by changing the refractive index of holes and it has been found that with increasing refractive index, wavelength position of transmission spectrum shifts. The radius and the shape of the air holes localized at each side of the line defect are optimized to realize high sensitivity, wide measurement range and improved transmission. An improved optofluidic sensor design is also described and a 210 nm wavelength position of upper band edge shift was observed corresponding to a sensitivity of more than 636 nm per refractive index unit (RIU)

    High sensitive photonic crystal multiplexed biosensor array using H0 sandwiched cavities

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    We theoretically investigate a high sensitive photonic crystal integrated biosensor array structure which is potentially used for label-free multiplexed sensing. The proposed device consists of an array of three sandwiched H0 cavities patterned above silicon on insulator (SOI) substrate; each cavity has been designed for different cavity spacing and different resonant wavelength. Results obtained by performing finite-difference time-domain (FDTD) simulations, indicate that the response of each detection unit shifts independently in terms of refractive index variations. The optimized design makes possible the combination of sensing as a function of location, as well as a function of time in the same platform. A refractive index sensitivity of 520nm/RIU and a quality factor over 104 are both achieved with an accompanied crosstalk of less than -26 dB. In addition, the device presents an improved detection limit (DL) of 1.24.10-6 RIU and a wide measurement range. These features make the designed device a promising element for performing label-free multiplexed detection in monolithic substrate for medical diagnostics and environmental monitoring

    High sensitive photonic crystal multiplexed biosensor array using H0 sandwiched cavities

    No full text
    We theoretically investigate a high sensitive photonic crystal integrated biosensor array structure which is potentially used for label-free multiplexed sensing. The proposed device consists of an array of three sandwiched H0 cavities patterned above silicon on insulator (SOI) substrate; each cavity has been designed for different cavity spacing and different resonant wavelength. Results obtained by performing finite-difference time-domain (FDTD) simulations, indicate that the response of each detection unit shifts independently in terms of refractive index variations. The optimized design makes possible the combination of sensing as a function of location, as well as a function of time in the same platform. A refractive index sensitivity of 520nm/RIU and a quality factor over 104 are both achieved with an accompanied crosstalk of less than -26 dB. In addition, the device presents an improved detection limit (DL) of 1.24.10-6 RIU and a wide measurement range. These features make the designed device a promising element for performing label-free multiplexed detection in monolithic substrate for medical diagnostics and environmental monitoring

    Contribution à l étude du bruit basse fréquence dans des hétérostructures AlGaAs/GaAs/AlGaAs

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    Le travail présenté dans ce mémoire a pour objet la caractérisation d un gaz bidimensionnel d électrons dans une hétérostructure AlGaAs/GaAs/AlGaAs par la méthode de bruit basse fréquence à des différentes tensions de polarisation et à différentes températures (4 - 300K). Plusieurs sources de bruit contribuant au spectre total de bruit (bruit thermique, bruit de génération - recombinaison (G-R) et bruit en 1/f) ont été identifiés. Grâce au bruit thermique, nous avons montré qu il est possible d accéder aux résistances de contact. L analyse du bruit de G-R a permis d identifier des défauts sources de ce type de bruit. Pour ce faire, il a fallu déterminer les énergies d activation thermiques et les sections efficaces de capture caractérisant ces défauts. L étude du bruit en 1/f a été faite de deux manières ; d abord l application du modèle de Hooge a permis de montrer que ce bruit est causé essentiellement par la fluctuation de la mobilité du réseau. Puis, l application du modèle modifié de Handel a permis de renforcer la proposition de la fluctuation de la mobilitéThe study presented in this manuscript is devoted to characterize a two dimensional electron gaz (2DEG) in a AlGaAs/GaAs/AlGaAs heterostructure by using the low frequency noise technique. The study was made for different bias voltages and at different temperatures (4 - 300 K). Several noise sources (thermal noise, generation-recombination noise (G-R) and 1/f noise) contributing to the total spectrum were identified. With thermal noise, we have shown that it was possible to access to the contact resistances. Analysis of the G-R noise has allowed identification of defects responsible of this noise. To do this, it was necessary to determine thermal activation energies and capture cross sections characterizing these defects. The study of 1/f noise was made in two ways: first, application of the Hooge model showed that this noise is mainly caused by the network mobility fluctuation. Then, applying the modified model of Handel has strengthened the proposal fluctuation of the mobilityREIMS-BU Sciences (514542101) / SudocSudocFranceF

    Four channel optical demultiplexer based on L2 photonic crystal microcavity

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    The wavelength demultiplexing is a particularly important function in integrated optics and can be realized using photonic crystals. The aim is to extract accurately the wavelengths in a data flux. In this work, we investigate a new topologies of wavelength demultiplexing based on two-dimensional photonic crystals constituted of dielectric rods spread in a square network. The studied demultiplexer is based on optical filters with optimized parameters in order to extract four different wavelengths in the vicinity of frequencies corresponding to communication windows. It was found that the crosstalk between the structure channels of the demultiplexer are in the range of –19.19 and – 44.1 dB and the channel spacing is equal to 0.96 nm. The simulation results presented in this paper are performed and analyzed using the FDTD method
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