9,882 research outputs found

    Integrated optics technology study

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    The status and near term potential of materials and processes available for the fabrication of single mode integrated electro-optical components are discussed. Issues discussed are host material and orientation, waveguide formation, optical loss mechanisms, wavelength selection, polarization effects and control, laser to integrated optics coupling fiber optic waveguides to integrated optics coupling, sources, and detectors. Recommendations of the best materials, technology, and processes for fabrication of integrated optical components for communications and fiber gyro applications are given

    Structured ZnO-based contacts deposited by non-reactive rf magnetron sputtering on ultra-thin SiO2/Si through a stencil mask

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    In this paper, we study the localized deposition of ZnO micro and nanostructures deposited by non-reactive rf-magnetron sputtering through a stencil mask on ultra-thin (10 nm) SiO2 layers containing a single plane of silicon nanocrystals (NCs), synthetized by ultra-low energy ion implantation followed by thermal annealing. The localized ZnO-deposited areas are reproducing the exact stencil mask patterns. A resistivity of around 5×10−3 Ω cm is measured on ZnO layer. The as-deposited ZnO material is 97% transparent above the wavelength at 400 nm. ZnO nanostructures can thus be used as transparent electrodes for Si NCs embedded in the gate-oxide of MOS devices

    Development of sputtered techniques for thrust chambers

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    Techniques and materials were developed and evaluated for the fabrication and coating of advanced, long life, regeneratively cooled thrust chambers. Materials were analyzed as fillers for sputter application of OFHC copper as a closeout layer to channeled inner structures; of the materials evaluated, aluminum was found to provide the highest bond strength and to be the most desirable for chamber fabrication. The structures and properties were investigated of thick sputtered OFHC copper, 0.15 Zr-Cu, Al2O3,-Cu, and SiC-Cu. Layered structures of OFHC copper and 0.15 Zr-Cu were investigated as means of improving chamber inner wall fatigue life. The evaluation of sputtered Ti-5Al-2.5Sn, NASA IIb-11, aluminum and Al2O3-Al alloys as high strength chamber outer jackets was performed. Techniques for refurbishing degraded thrust chambers with OFHC copper and coating thrust chambers with protective ZrO2 and graded ZrO2-copper thermal barrier coatings were developed

    Design, fabrication and characterization of a distributed Bragg reflector for reducing the Ă©tendue of a wavelength converting system

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    In this work, the design, fabrication and characterization are reported for a distributed Bragg reflector (DBR) filter with a specific wavelength and angular dependency, which aims to improve the light collection from a wavelength-converter-based light source into a smaller angle than the full angle Lambertian emission. The desired design is obtained by optimizing the transmission characteristics of a multi-layer structure. Titania (TiO2) and silica (SiO2) are used as high and low refractive index materials, respectively. The deposition is made by electron beam evaporation without substrate heating, followed by a post-annealing procedure. The optical properties of the evaporated layers are analyzed by ellipsometer and spectrometer measurements. The angular and wavelength dependency of the fabricated DBR is in good agreement with simulations for the designed structure. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen

    Fabrication of high quality sub-micron Au gratings over large areas with pulsed laser interference lithography for SPR sensors

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    Metallic gratings were fabricated using high energy laser interference lithography with a frequency tripled Nd:YAG nanosecond laser. The grating structures were first recorded in a photosensitive layer and afterwards transferred to an Au film. High quality Au gratings with a period of 770 nm and peak-to-valley heights of 20-60 nm exhibiting plasmonic resonance response were successfully designed, fabricated and characterized.Comment: 10 pages, 7 figure

    WO3-decorated ZnO nanostructures for light-activated applications

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    In the present work, a two-step vapor-phase route was implemented for the tailored design of ZnO\u2013WO3 nanoheterostructures supported on fluorine-doped tin oxide (FTO) substrates. Under optimized conditions, the sequential use of chemical vapor deposition (CVD) and radio frequency (RF)-sputtering for the deposition of zinc and tungsten oxides respectively, resulted in the growth of calyx-like ZnO nanostructures uniformly decorated by a conformal dispersion of low-sized WO3 nanoparticles. The target materials were characterized by means of a multi-technique approach, with particular regard to their structural, compositional, morphological and optical properties. Finally, their photocatalytic performances were preliminarily tested in the abatement of NOX gases (NO and NO2). Due to the unique porous morphology of the ZnO nanodeposit and the high density of ZnO\u2013WO3 heterojunctions, WO3-decorated ZnO revealed appealing De-NOX characteristics in terms of both degradation efficiency and selectivity. Such features, along with the photoinduced superhydrophilicity and self-cleaning properties of the present nanomaterials, candidate them as promising functional platforms for applications in smart windows and building materials for environmental remediation
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