Browsing NTNU Open by Author "Laurell, Fredrik"

Now showing items 1-9 of 9

    • Broadband infrared and THz transmitting silicon core optical fiber 

      Sørgård, Trygve; Song, Seunghan; Vullum, Per Erik; Kores, Cristine; Mølster, Kjell Martin; Laurell, Fredrik; Hawkins, Thomas A.; Ballato, John; Österberg, Ulf Lennart; Gibson, Ursula (Peer reviewed; Journal article, 2020)
      Silicon waveguide structures are a viable alternative for the transmission of signals over a wide range of frequencies, and new fabrication methods are key to increased applications. In this work, THz transparency of ...

    • CO2 laser annealed SiGe core optical fibers with radial Ge concentration gradients 

      Wu, Wei; Balci, Mustafa H.; Song, Seunghan; liu, chunxin; Fokine, Michael; Laurell, Fredrik; Hawkins, Thomas A.; Ballato, John; Gibson, Ursula (Peer reviewed; Journal article, 2020)
      CO2 laser annealing of SiGe core, glass-clad optical fibers is a powerful technique for the production of single-crystal cores with spatially varying Ge concentrations. Laser power, laser scan speed and cooling air flow ...

    • Crystalline GaSb-core optical fibers with room-temperature photoluminescence 

      Song, Seunghan; Healy, Noel; Svendsen, Silje; Österberg, Ulf; Cuervo Covian, Alejandra; Liu, Jifeng; Peacock, Anna; Ballato, John; Laurell, Fredrik; Fokine, Michael; Gibson, Ursula (Journal article; Peer reviewed, 2018)
      Glass-clad, GaSb-core fibers were drawn and subsequently laser annealed. The asdrawn fibers were found to be polycrystalline, possess Sb inclusions, and have oxide contamination concentrations of less than 3 at%. Melting ...

    • Ge-capped SiGe core optical fibers 

      Wu, Wei; Balci, Mustafa H.; Muhlberger, Korbinian; Fokine, Michael; Laurell, Fredrik; Hawkins, Thomas A.; Ballato, John; Gibson, Ursula (Journal article; Peer reviewed, 2019)
      CO2 laser processing offers the possibility to inscribe structures within glass-clad SiGe-core fibers by altering the spatial distribution of the Si and Ge. Spatial segregation of Ge to the end of a fiber is shown via ...

    • Laser restructuring and photoluminescence of glass-clad GaSb/Si-core optical fibres 

      Song, Seunghan; Lønsethagen, Kristin; Laurell, Fredrik; Hawkins, Thomas A.; Ballato, John; Fokine, Michael; Gibson, Ursula (Journal article; Peer reviewed, 2019)
      Semiconductor-core optical fibres have potential applications in photonics and optoelectronics due to large nonlinear optical coefficients and an extended transparency window. Laser processing can impose large temperature ...

    • Localised structuring of metal-semiconductor cores in silica clad fibres using laser-driven thermal gradients 

      Song, Seunghan; Laurell, Fredrik; Meehan, Bailey; Hawkins, Thomas A.; Ballato, John; Gibson, Ursula (Peer reviewed; Journal article, 2022)
      The molten core drawing method allows scalable fabrication of novel core fibres with kilometre lengths. With metal and semiconducting components combined in a glass-clad fibre, CO2 laser irradiation was used to write ...

    • 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.

    • 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 ...

    • Time-domain spectroscopy of KTiOPO4 in the frequency range 0.6 - 7.0 THz 

      Mølster, Kjell Martin; Sørgård, Trygve; Laurell, Hugo; Canalias, Carlota; Pasiskevicius, Valdas; Laurell, Fredrik; Österberg, Ulf Lennart (Journal article; Peer reviewed, 2019)
      We report on THz time-domain spectroscopy measurements of flux grownKTiOPO4in the frequency range 0.6–7.0 THz (20 to 240 cm−1). Our results compare well with earlierRaman and far-infrared measurements. We theorize that the ...