Blar i NTNU Open på forfatter "Gibson, Ursula"
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MBE-grown Cr:ZnS Thin Film Laser Media
Tolstik, Nikolai; Sorokin, Evgeni; Karhu, Eric Andrew; Polyakov, Stanislav; Gibson, Ursula; Sorokina, Irina T (Chapter, 2016)We report results of spectroscopic analysis of the first first laser-quality MBE-grown Cr:ZnS films. Comparison of spectral-luminescent properties with bulk Cr:ZnS indicates their good laser properties, opening the way ... -
Molecular beam and pulsed laser deposition of ZnS:Cr for intermediate band solar cells
Nematollahi, Mohammadreza; Yang, Xiaodong; Aas, Lars Martin Sandvik; Ghadyani, Zahra; Kildemo, Morten; Gibson, Ursula; Reenaas, Turid Worren (Journal article, 2015)We have investigated the structural and optical properties of Cr-doped ZnS (ZnS:Cr) thin films (0–7.5 at.% Cr) for use in intermediate band solar cells. The films were grown on Si(100) in molecular beam epitaxy (MBE) and ... -
Net optical parametric gain in a submicron silicon core fiber pumped in the telecom band
Wu, Dong; Shen, Li; Ren, Haonan; Campling, Joseph; Hawkins, Thomas; Ballato, John; Gibson, Ursula; Peacock, Anna (Peer reviewed; Journal article, 2019)A silicon core fiber (SCF) has been designed and fabricated with a dispersion engineered profile to support broadband optical parametric amplification across the telecom window. The combination of low optical transmission ... -
Nonlinear optical properties of polycrystalline silicon core fibers from telecom wavelengths into the mid-infrared spectral region
Ren, Haonan; Shen, Li; Wu, D; Aktas, Ozan; Hawkins, Thomas A.; Ballato, John; Gibson, Ursula; Peacock, Anna (Journal article; Peer reviewed, 2019)Polycrystalline silicon core fibers (SCFs) fabricated via the molten core drawing (MCD) method are emerging as a flexible optoelectronic platform. Here, the optical transmission properties of MCD SCFs that have been tapered ... -
Nonlinear optical response and structural properties of MBE-grown Fe:ZnS films
Polyakov, Stanislav; Karhu, Eric Andrew; Zamiri, Reza; Moisset, Charles; Iliopoulos, Konstantinos; Vullum, Per Erik; Österberg, Ulf; Gibson, Ursula (Journal article; Peer reviewed, 2018)Fe-doped ZnS films of high optical quality were fabricated using vacuum vapor deposition. Preferential crystalline orientation and phase purity of the host ZnS films were increased by the addition of small amounts of Fe, ... -
Optical Coatings as Active Media for Mid-Infrared lasers
Karhu, Eric Andrew; Tolstik, Nikolai; Sorokin, Evgeni; Furtula, Vedran; Sorokina, Irina T.; Gibson, Ursula (Chapter, 2016)Thin films of Cr and Fe-doped ZnS with high infrared transparency have been deposited by molecular beam epitaxy and show optical properties suitable for use as active media in mid-infrared laser applications. -
Optical coatings for enhancement of the longitudinal Magneto-optic Kerr Effect from magnetic ultra-thin films
Tveten, Erlend Grytli (Master thesis, 2011)The effect of optical coatings on the longitudinal magneto-optic Kerr effect response from 10 nm thin films of permalloy (Ni84Fe16) has been studied. Enhancement of the magneto-optic Kerr effect signal contrast of a factor ... -
Optical Properties and Composition of Fe:ZnS Films
Molland, Nelly-Ann (Master thesis, 2014)Iron doped ZnS thin films were deposited using the physical vapor deposition technique over a concentration range of 0-12% Fe. The thickness and composition of the films were measured with a profilometer and EDS, respectively, ... -
Optical Properties of Silicon Microwire Arrays for Photovoltaic Applications
Smeltzer, Benjamin (Master thesis, 2015)Silicon microwire-based solar cells represent a potential design strategy to reduce wafer related costs through reduced material usage and relaxed purity requirements. In this work we investigate the absorption of incident ... -
Properties of Transition Metal Substituted Zinc Sulfide Hexamers and Dodecamers
Poggio, Stefano; Wang, Brendan; Gibson, Ursula; BelBruno, Joseph (Journal article, 2015)Density functional theory was used to study the structural and electronic properties of endohedrally- and substitutionally-doped Zn6S6 and Zn12S12 clusters with first-row transition metal atoms. Generally, the lowest energy ... -
Pulsed laser ablation and deposition of ZnS:Cr
Nematollahi, Mohammadreza; Yang, Xiaodong; Gibson, Ursula; Reenaas, Turid Worren (Journal article; Peer reviewed, 2015)We present a method to deposit films with a range of doping concentrations/dilute alloys, from a single target in pulsed laser deposition (PLD). Cr-doped ZnS films were deposited by ablating a target consisting Cr particles ... -
Pump-probe experiments of multicrystalline silicon for solar cell applications
Henriksen, Lisa Grav (Master thesis, 2012)In order to make cost effective solar cells from mc-Si materials, the negative contributions from defects and impurities should be reduced. The analysis of the photogenerated carrier properties is therefore of great ... -
Rapid Directional Recrystallisation of SiGe Fibres
Coucheron, David Andre (Master thesis, 2015)Fibre av \ce{SiGe} fremstilt ved flytende kjerne-trekking har blitt rekrystallisert ved bruk av to forskjellige teknikker: Sakte kj{\o}ling i en tubeovn og bevegende smeltesone-rekrystallisering med en \ce{CO2}-laser. To ... -
Recrystallization of silicon core fibers by CO2 laser annealing
Lønsethagen, Kristin (Master thesis, 2017)The innovation of introducing silicon in the core of optical glass fibers has lately been of great interest to the optoelectronics industry. The application areas of silicon core fibers are ranging from medical imaging and ... -
Rotation of the onion state in micromagnetic rings
Nesse, Torstein (Master thesis, 2013)The behavior of the movement of the two domain walls that make up the onion state in 5 μm Permalloy rings have been studied under rotation using longitudinal magneto-optical Kerr effect. Resistance to the domain wall motion ... -
Semiconductor core fibres: materials science in a bottle
Gibson, Ursula; Wei, Lei; Ballato, John (Peer reviewed; Journal article, 2021)Novel core fibers have a wide range of applications in optics, as sources, detectors and nonlinear response media. Optoelectronic, and even electronic device applications are now possible, due to the introduction of methods ... -
Si/GaSb Micro Core Glass fiber
Song, Seunghan (Master thesis, 2017)Semiconductor core glass fibers are a promising platform for optoelectronic and optical applications with an enormous potential. Glass fibers with homogeneous semiconductor cores have mainly studied so far, but recent ... -
Silicon Core Optical Fibre Production and Characterisation: An investigation of alkali earth metal oxide interface additives in a fibre production method.
Dibbs, Andrew (Master thesis, 2013)Solid semiconductor optical fibres are of interest for infrared transmission and guided wave photonics. High transmission of light in the 2-6 micrometer wavelength region in optical fibres is difficult with today's materials, ... -
Silicon Optical Fibres - Past, Present and Future
Peacock, Anna; Gibson, Ursula; Ballato, John (Journal article; Peer reviewed, 2016)This paper reviews the past, present and prospective future of silicon optical fibres. The incorporation of silicon with its rich optoelectronic functionality into existing glass fibre technologies presents a route to ... -
Silicon-core glass fibres as microwire radial-junction solar cells
Martinsen, Fredrik A; Smeltzer, Benjamin; Nord, Magnus Kristofer; Hawkins, Thomas A.; Ballato, John; Gibson, Ursula (Journal article; Peer reviewed, 2014)Vertically aligned radial-junction solar cell designs offer potential improvements over planar geometries, as carrier generation occurs close to the junction for all absorption depths, but most production methods still ...