Blar i NTNU Open på forfatter "Gibson, Ursula"

Viser treff 61-70 av 70

    • Single crystal semiconductor-core optical fiber* 

      Wu, Wei; Song, Seunghan; Balci, Mustafa H.; Laurell, Fredrik; Cantwell, Patrick; Ballato, John; Gibson, Ursula (Journal article; Peer reviewed, 2019)
      Semiconductor-core fibers are improved by removal of grain boundaries. We use a CO2 laser to process silicon-based cores; an alloying element reduces both the temperature and speed required for formation of a single crystal.

    • Spectral-luminescent properties of vapor deposited Cr:ZnS thin films and their application as saturable absorbers for 1.5-μm erbium lasers 

      Tolstik, Nikolai; Sorokin, Evgeni; Karhu, Eric Andrew; Gorbachenya, Konstantin N.; Polyakov, Stanislav; Kisel, Victor E.; Kuleshov, Nikolai V.; Furtula, Vedran; Gibson, Ursula; Sorokina, Irina T (Journal article; Peer reviewed, 2018)
      We report the results of the extensive spectral-luminescent characterization including concentration quenching analysis of the first laser-quality vapor-deposited Cr:ZnS films, and demonstrate their use as saturable ...

    • Tapered silicon core fibers with nano-spikes for optical coupling via spliced silica fibers 

      Ren, Haonan; Aktas, Ozan; Franz, Yohann; Runge, Antoine; Hawkins, Thomas A.; Ballato, John; Gibson, Ursula; Peacock, Anna (Journal article; Peer reviewed, 2017)
      Abstract: Reported here is the fabrication of tapered silicon core fibers possessing a nanospike input that facilitates their seamless splicing to conventional single mode fibers. A proofof-concept 30 µm cladding diameter ...

    • Temperature coefficients in compensated silicon materials for solar cells 

      Skomedal, Åsmund (Master thesis, 2017)
      The pricing of solar modules is closely connected to the rating at standard testing conditions (STC). Lately more emphasis has been put on the relationship between field performance of PV-modules and the temperature ...

    • Terahertz Time-Domain Spectroscopy of Thin Material Samples 

      Sørgård, Trygve Reinertsen (Master thesis, 2015)
      This thesis describes the techniques used in terahertz time-domain spectroscopy to determine the optical properties of layers that are thin compared to the length of the terahertz pulse. An iterative procedure is used to ...

    • Terahertz waveguiding in glass+clad silicon wafers 

      Sørgård, Trygve; Mølster, Kjell Martin; Laurell, Fredrik; Pasiskevicius, Valdas; Gibson, Ursula; Österberg, Ulf Lennart (Journal article; Peer reviewed, 2020)
      The waveguiding properties of high-resistivity float zone silicon slab waveguides are characterized over the spectral range from 0.5 to 7.5 THz. Waveguide modes and dispersion are observed for lengths of 1.2 cm and silicon ...

    • Thermal processing of semiconductor alloy core glass fibers 

      Song, Seunghan (Doctoral theses at NTNU;2021:409, Doctoral thesis, 2021)
      Semiconductor core glass-clad fibers are of great interest as optical and optoelectronic platforms for their high transparency in infrared and the potential control of their electrical properties by doping or strain ...

    • Towards Mid-IR Waveguide Lasers: Transition Metal Doped ZnS Thin Films 

      Karhu, Eric Andrew; Tolstik, Nikolai; Sorokin, Evgeni; Polyakov, Stanislav; Zamiri, Reza; Furtula, Vedran; Østerberg, Ulf Lennart; Sorokina, Irina T; Gibson, Ursula (Chapter; Peer reviewed, 2016)
      Thin films of Cr and Fe-doped ZnS suitable for waveguide mid-IR applications, with well-isolated TM2+ peaks, and Cr2+ absorption and fluorescence comparable to bulk crystals were investigated. Raman data indicate that the ...

    • Vapor deposited Cr-doped ZnS thin films: Towards optically pumped mid-infrared waveguide lasers 

      Karhu, Eric Andrew; Ildstad, Charles Rutherford; Poggio, Stefano; Furtula, Vedran; Tolstik, Nikolai; Sorokina, Irina T; BelBruno, Joseph; Gibson, Ursula (Journal article; Peer reviewed, 2016)
      Compact, affordable mid-IR lasers require the development of gain materials in waveguide form. We report on the high vacuum deposition of Cr:ZnS films with concentration ranging from 1018-1020 dopants/cm3 . At low ...

    • Wavelength conversion and supercontinuum generation in silicon optical fibers 

      Peacock, Anna; Campling, Joseph; Runge, Antoine; Ren, Haonan; Shen, Li; Aktas, Ozan; Horak, Peter; Healy, Noel; Gibson, Ursula; Ballato, John (Journal article, 2018)
      This paper describes the state of the art in wavelength conversion and supercontinuum generation using glass-clad silicon core optical fibers. Such semiconductor fibers have enjoyed considerable attention due to their ...