Aasmund Sudbø

• Gliss, Jonas; Stebel, Kerstin; Kylling, Arve & Sudbø, Aasmund (2018). Improved optical flow velocity analysis in SO2 camera images of volcanic plumes – implications for emission-rate retrievals investigated at Mt Etna, Italy and Guallatiri, Chile. Atmospheric Measurement Techniques.  ISSN 1867-1381.  11(2), s 781- 801 . doi: 10.5194/amt-11-781-2018 Fulltekst i vitenarkiv. Vis sammendrag

  Accurate gas velocity measurements in emission plumes are highly desirable for various atmospheric remote sensing applications. The imaging technique of UV SO2 cameras is commonly used to monitor SO2 emissions from volcanoes and anthropogenic sources (e.g. power plants, ships). The camera systems capture the emission plumes at high spatial and temporal resolution. This allows the gas velocities in the plume to be retrieved directly from the images. The latter can be measured at a pixel level using optical flow (OF) algorithms. This is particularly advantageous under turbulent plume conditions. However, OF algorithms intrinsically rely on contrast in the images and often fail to detect motion in low-contrast image areas. We present a new method to identify ill-constrained OF motion vectors and replace them using the local average velocity vector. The latter is derived based on histograms of the retrieved OF motion fields. The new method is applied to two example data sets recorded at Mt Etna (Italy) and Guallatiri (Chile). We show that in many cases, the uncorrected OF yields significantly underestimated SO2 emission rates. We further show that our proposed correction can account for this and that it significantly improves the reliability of optical-flow-based gas velocity retrievals. In the case of Mt Etna, the SO2 emissions of the north-eastern crater are investigated. The corrected SO2 emission rates range between 4.8 and 10.7 kg s−1 (average of 7.1  ±  1.3 kg s−1) and are in good agreement with previously reported values. For the Guallatiri data, the emissions of the central crater and a fumarolic field are investigated. The retrieved SO2 emission rates are between 0.5 and 2.9 kg s−1 (average of 1.3  ±  0.5 kg s−1) and provide the first report of SO2 emissions from this remotely located and inaccessible volcano.

• Gliss, Jonas; Stebel, Kerstin; Kylling, Arve; Dinger, Anna Solveig; Sihler, H. & Sudbø, Aasmund (2017). Pyplis — A Python software toolbox for the analysis of SO2 camera images for emission rate retrievals from point sources. Geosciences.  ISSN 2076-3263.  7(4) . doi: 10.3390/geosciences7040134 Fulltekst i vitenarkiv.
• Grepstad, Jon Olav; Gjessing, Jo; Angelskår, Hallvard; Skokic, Zeljko; Bakke, Thor & Sudbø, Aasmund (2016). Design and simulation of efficient narrowband thermal emitter with 3 μm wavelength, In  2016 Conference on Lasers and Electro-Optics (CLEO), San Jose; United States, 5-10 June 2016.  IEEE.  ISBN 978-1-5090-2434-6.  artikkel. Vis sammendrag

  A low-power infrared source based on a silicon photonic-crystal membrane has been designed. Temperature distribution and reflection spectrum has been simulated. Large narrowband IR absorption is obtained with optimal material doping

• Grepstad, Jon Olav; Greve, Martin Møller; Holst, Bodil; Johansen, Ib-Rune; Solgaard, Olav & Sudbø, Aasmund (2013). Finite-size limitations on quality factor of guided resonance modes in 2D photonic crystals. Optics Express.  ISSN 1094-4087.  21(20), s 23640- 23654 . doi: 10.1364/OE.21.023640 Fulltekst i vitenarkiv. Vis sammendrag

  High-Q guided resonance modes in two-dimensional photonic crystals, enable high field intensity in small volumes that can be exploited to realize high performance sensors. We show through simulations and experiments how the Q-factor of guided resonance modes varies with the size of the photonic crystal, and that this variation is due to loss caused by scattering of in-plane propagating modes at the lattice boundary and coupling of incident light to fully guided modes that exist in the homogeneous slab outside the lattice boundary. A photonic crystal with reflecting boundaries, realized by Bragg mirrors with a band gap for in-plane propagating modes, has been designed to suppress these edge effects. The new design represents a way around the fundamental limitation on Q-factors for guided resonances in finite photonic crystals. Results are presented for both simulated and fabricated structures.

• Grepstad, Jon Olav; Kaspar, Peter; Johansen, Ib-Rune; Solgaard, Olav & Sudbø, Aasmund (2013). Detection of single nano-defects in photonic crystals between crossed polarizers. Optics Express.  ISSN 1094-4087.  21(25), s 31375- 31389 . doi: 10.1364/OE.21.031375 Fulltekst i vitenarkiv. Vis sammendrag

  We investigate, by simulations and experiments, the light scattering of small particles trapped in photonic crystal membranes supporting guided resonance modes. Our results show that, due to amplified Rayleigh small particle scattering, such membranes can be utilized to make a sensor that can detect single nano-particles. We have designed a biomolecule sensor that uses cross-polarized excitation and detection for increased sensitivity. Estimated using Rayleigh scattering theory and simulation results, the current fabricated sensor has a detection limit of 26 nm, corresponding to the size of a single virus. The sensor can potentially be made both cheap and compact, to facilitate use at point-of-care.

• Grepstad, Jon Olav; Kaspar, Peter; Solgaard, Olav; Johansen, Ib-Rune & Sudbø, Aasmund (2013). Single nano-particle sensing exploiting crossed polarizers to improve the signal-to-noise ratio, In of America Optical Society (ed.),  CLEO:2013 Laser Science to photonic applications.  Optics Info Base, Optical Society of America.  ISBN 978-1-55752-972-5.  artikkel.  s CM1M.2 Vis sammendrag

  Crossed polarized excitation and detection has been used to improve signal-tonoise ratio in an optical nano-particle sensor exploiting guided-resonance-modes in photonic crystal membranes. The sensor can detect particles with a diameter less than 40 nm

• Grepstad, Jon Olav; Kaspar, Peter; Johansen, Ib-Rune & Sudbø, Aasmund (2012). Optical Imaging System Designed for Biosensing using a Photonic Crystal Membrane to Detect Nanoparticles, In  2012 Imaging and Applied Optics Congress.  Optical Society of Amerika.  ISBN 1-55752-947-7.  Conference Paper. Vis sammendrag

  We have built an optical microscope for a new biosensor application, incorporating a 2D photonic crystal membrane enabling detection of particles with a radius less than 50 nm. The microscope has been characterized experimentally.

• Grepstad, Jon Olav; Kaspar, Peter; Solgaard, Olav; Johansen, Ib-Rune & Sudbø, Aasmund (2012). Photonic-crystal membranes for optical detection of single nano-particles, designed for biosensor application. Optics Express.  ISSN 1094-4087.  20(7), s 7954- 7965 . doi: 10.1364/OE.20.007954 Fulltekst i vitenarkiv. Vis sammendrag

  A sensor designed to detect bio-molecules is presented. The sensor exploits a planar 2D photonic crystal (PC) membrane with sub-micron thickness and through holes, to induce high optical fields that allow detection of nano-particles smaller than the diffraction limit of an optical microscope. We report on our design and fabrication of a PC membrane with a nano-particle trapped inside. We have also designed and built an imaging system where an optical microscope and a CCD camera are used to take images of the PC membrane. Results show how the trapped nano-particle appears as a bright spot in the image. In a first experimental realization of the imaging system, single particles with a radius of 75 nm can be detected.

• Grepstad, Jon Olav; Kaspar, Peter; Solgaard, Olav; Johansen, Ib-Rune & Sudbø, Aasmund (2012). Enhanced scattering from nano-particles trapped in photonic crystal membranes, In  2012 International Conference on Optical MEMS and Nanophotonics (OMN), Banff, AB, 6-9 Aug. 2012.  IEEE conference proceedings.  ISBN 978-1-4577-1511-2.  Artikkel.  s 21 - 22 Vis sammendrag

  We present simulations showing how light scattered by isolated particles increases by a factor 10, when they are placed in photonic crystal membranes. Exploiting this effect, single nano-particles have been detected with an optical microscope.

• Kim, Sora; Hadzialic, Sanja; Sudbø, Aasmund & Solgaard, Olav (2012). Reflectivity and polarization dependence of polysilicon single-film broadband photonic crystal micro-mirrors. Optics Express.  ISSN 1094-4087.  20(6), s 6306- 6315 . doi: 10.1364/OE.20.006306 Fulltekst i vitenarkiv. Vis sammendrag

  We report on the fabrication of 2-D photonic crystal (PC) micro-mirrors, and Finite Difference Time Domain (FDTD) simulations and measurements of their reflectance spectra and polarization dependence at normal incidence. The PC mirrors were fabricated in free-standing thin polysilicon membranes supported by silicon nitride films for stress compensation. Greater than 90% reflectivity is measured over a wavelength range of 35 nm from 1565 nm to 1600 nm with small polarization dependence. Our FDTD simulations show that fabrication errors on the order of tens of nanometers can strongly affect the reflection spectra. When the fabrication errors are kept below this level, FDTD simulations on perfectly periodic structures accurately predict the reflection spectra of the fabricated PC mirrors, despite their sensitivity to the fabrication errors.

• Marstein, Erik Stensrud; Selj, Josefine Helene; Gjessing, Jo; Haug, Halvard & Sudbø, Aasmund (2012). Light management in thin crystalline silicon solar cells, In  27th European Photovoltaic Solar Energy Conference (EU PVSEC), Frankfurt, Germany, September, 2012.  WIP - Renewable Energies.  ISBN 3-936338-28-0.  Paper.  s 2049 - 2052 Vis sammendrag

  In order to reduce the costs of solar cells, there is a strong drive towards the use of thinner absorber materials. Crystalline silicon materials have already proven highly attractive as absorbers in mass produced, low cost and efficient solar cells. However as absorbers become thinner, crystalline silicon solar cells increasingly suffer from optical losses related to transmission, which again lead to losses in short circuit current density and efficiency. In this work, recent developments of structures for managing light in co-planar, ultrathin crystalline silicon substrates made in our group will be presented. We will show that the light trapping can be dramatically enhanced in ultrathin crystalline silicon wafers by incorporating periodic nanostructures on a solar cell rear side covered with a surface-passivating dielectric and metal mirror. To allow for simplified module and solar cell processing with such structures, we have aimed at developing a co-planar solar cell structure. Unfortunately, without proper measures, the resulting increases in front side reflectance will cancel out any gain in light trapping. We will therefore also show that a multilayer thin film anti-reflection coating (ARC) structure can sufficiently reduce front side reflection in a solar cell and module environment.

• Gjessing, Jo; Sudbø, Aasmund Sveinung & Marstein, Erik Stensrud (2011). A novel back-side light trapping structure for thin silicon solar cells. Journal of the European Optical Society - Rapid Publications.  ISSN 1990-2573.  6 . doi: 10.2971/jeos.2011.11020 Fulltekst i vitenarkiv.
• Gjessing, Jo; Sudbø, Aasmund Sveinung & Marstein, Erik Stensrud (2011). Comparison of periodic light-trapping structures in thin crystalline silicon solar cells. Journal of Applied Physics.  ISSN 0021-8979.  110(3) . doi: 10.1063/1.3611425 Fulltekst i vitenarkiv.
• Tonheim, Celin Russøy; Sudbø, Aasmund Sveinung; Selvig, Espen & Haakenaasen, Randi (2011). Enhancement in Light Emission From Hg-Cd-Te Due to Surface Patterning. IEEE Photonics Technology Letters.  ISSN 1041-1135.  23(1), s 36- 38 . doi: 10.1109/LPT.2010.2090517
• Angelskår, Hallvard; Johansen, Ib-Rune; Lacolle, Matthieu Jean P & Sudbø, Aasmund Sveinung (2010). Wood's anomalies and spectral uniformity of focusing diffractive optical elements. Optics Express.  ISSN 1094-4087.  18(16), s 17201- 17208 Fulltekst i vitenarkiv. Vis sammendrag

  We report on simulations and measurements of focusing diffractive optical elements, fabricated as two-level binary optics. The diffractive optical elements are designed to separate and focus four specific wavelengths in the infrared. The simulations are based on a local linear grating model, and predict anomalies similar to Wood’s anomalies known from grating diffraction theory. The anomalies are also seen in the measurements, and are excited at the DOE locations predicted by the simulations. The given examples illustrate the usefulness of the model for evaluation of DOE designs. We also present a comparison of the response and spectral uniformity between two different versions of the four-wavelength diffractive optical elements. In the first version, the optical functions for all the four wavelengths are incorporated into the same surface pattern, covering the whole patterned area. In the second version the pattern, each wavelength is kept separate, and cover one fourth of the area, forming a mosaic of the four individual patterns.

• Gjessing, Jo; Marstein, Erik Stensrud & Sudbø, Aasmund Sveinung (2010). 2D back-side diffraction grating for improved light trapping in thin silicon solar cells. Optics Express.  ISSN 1094-4087.  18(6), s 5481- 5495 Fulltekst i vitenarkiv. Vis sammendrag

  Light-trapping techniques can be used to improve the efficiency of thin silicon solar cells. We report on numerical investigation of a light trapping design consisting of a 2D back-side diffraction grating in combination with an aluminum mirror and a spacing layer of low permittivity to minimize parasitic absorption in the aluminum. The light-trapping design was compared to a planar reference design with anti-reflection coating and back-side aluminum mirror. Both normally and obliquely incident light was investigated. For normal incidence, the light trapping structure increases the short circuit current density with 17% from 30.4 mA/cm^2 to 35.5 mA/cm^2 for a 20 µm thick silicon solar cell. Our design also increases the current density in thinner cells, and yields higher current density than two recently published designs for cell thickness of 2 and 5 µm, respectively. The increase in current may be attributed to two factors; increased path length due to in-coupling of light, and decreased parasitic absorption in the aluminum due to the spacing layer.

• Hadzialic, Sanja; Kim, S; Sarioglu, AF; Sudbø, Aasmund Sveinung & Solgaard, Olav (2010). Displacement Sensing With a Mechanically Tunable Photonic Crystal. IEEE Photonics Technology Letters.  ISSN 1041-1135.  22(16), s 1196- 1198 . doi: 10.1109/LPT.2010.2050584 Vis sammendrag

  We demonstrate a mechanically tunable photonic crystal (PC) designed for highly position-sensitive reflection. Our device consists of a multilayer PC membrane attached to a silicon microelectromechanical system structure for lateral actuation. Inside each of the PC holes there is a pillar, which is attached to the substrate. By moving the PC membrane with respect to the pillars we change the shape of the PC holes and thereby modulate the PC reflectivity. Our measurements show a reflectivity change of more than 80% for a 115-nm lateral displacement.

• Hadzialic, Sanja; Kim, Sora; Sudbø, Aasmund Sveinung & Solgaard, Olav (2010). Two-Dimensional Photonic Crystals Fabricated in Monolithic Single-Crystal Silicon. IEEE Photonics Technology Letters.  ISSN 1041-1135.  22(2), s 67- 69 . doi: 10.1109/LPT.2009.2036143 Vis sammendrag

  We describe the fabrication of photonic crystals (PCs) in monolithic single-crystal Si on standard wafers without the need for silicon-on-insulator materials, and we demonstrate two types of PC devices based on this technology. The first is a PC mirror that exhibits broadband high reflectivity in the telecommunication wavelength band (> 90% from 1420 to 1520 nm). The second device shows large changes in reflectivity over narrow wavelength regions and has a sharp (3.5 nm wide) reflection minimum around 1550 nm, making the PC well suited for sensor applications. In both types of PC devices, guided resonances in the PC slab are exploited to obtain the desired reflection response. The PCs are fabricated in a process consisting of a series of oxidation and etch steps, with only one initial lithographic mask. The resulting PC slabs are monolithic structures, with the advantages of very thin and flat membranes with low internal stress, no temperature expansion coefficient mismatch, and compatibility with microelectromechanical systems and complementary metal–oxide–semiconductor processing.

• Angelskår, Hallvard; Johansen, Ib-Rune; Lacolle, Matthieu Jean P; Sagberg, Håkon & Sudbø, Aasmund Sveinung (2009). Spectral uniformity of two- and four-level diffractive optical elements for spectroscopy. Optics Express.  ISSN 1094-4087.  17(12), s 10206- 10222 Vis sammendrag

  We present simulations and characterization of gold coated diffractive optical elements (DOEs) that have been designed and fabricated in silicon for an industrial application of near-infrared spectroscopy. The DOE design is focusing and reflecting, and two-level and four-level binary designs were studied. Our application requires the spectral response of the DOE to be uniform over the DOE surface. Thus the variation in the spectral response over the surface was measured, and studied in simulations. Measurements as well as simulations show that the uniformity of the spectral response is much better for the four-level design than for the two-level design. Finally, simulations and measurements show that the four-level design meets the requirements of spectral uniformity from the industrial application, whereas the simulations show that the physical properties of diffraction gratings in general make the simpler two-level design unsuitable.

• Blad, Jakob & Sudbø, Aasmund Sveinung (2009). Evanescent modes in out-of-plane band structure for two-dimensional photonic crystals. Optics Express.  ISSN 1094-4087.  17(9), s 7170- 7185 . doi: http://www.opticsinfobase.org/oe/viewmedia.cfm?URI=oe-17-9-7170&seq=0 Vis sammendrag

  Reflection, diffraction and transmission of optical waves at the interface between a photonic crystal and the surrounding air can be described by propagating and evanescent Bloch modes. We have found such modes for one of the canonical two-dimensional photonic crystals, identical circular cylinders in a square pattern. We present computed out-of-plane band diagrams for propagating as well as evanescent modes, obtained with a numerical method based on Fourier-Bessel expansions. For a given frequency, all the modes are evanescent, except for a few low-order propagating modes. We find that most of the evanescent modes have a purely imaginary z-component of the Bloch wave vector, but many of the modes have a complex z-component.

• Angelskår, Hallvard & Sudbø, Aasmund Sveinung (2008). Spectral resolution of optical filters based on diffractive optical elements with non-uniform illumination. Journal of the European Optical Society - Rapid Publications.  ISSN 1990-2573.
• Clausen, Ingelin; Sveen, Ola & Sudbø, Aasmund Sveinung (2006). Protective coating for a piezorensistive pressure sensor intended for permanent implantation into the human brain, In  An implanted micro electro mechanical system for permanent measurement of human brain pressure.  Unipub forlag.  Paper IV.

Se alle arbeider i Cristin

• Sudbø, Aasmund (2019). Om harmoni i song og musikk. Fra Fysikkens Verden.  ISSN 0015-9247.  81(3), s 69- 71 Vis sammendrag

  Artikkelen set harmoni i song og musikk i samanheng med omgrepa samstemming, overtonar og skalatypar og drøftar tilhøyrande frekvensforhold.

• Sudbø, Aasmund (2019). Tenkegenet. Naturen.  ISSN 0028-0887.  143(2), s 62- 65 Vis sammendrag

  Huntingtons sykdom (HS) er en arvelig sykdom som angriper hjernen. Sykdommen har gjenkjennelige symptomer som ufrivillige bevegelser, rykninger og ustø gange. Sykdommen rammer individ som har for mange repetisjoner av en molekyltriplett i et spesifikt gen i arvestoffet DNA. En DNA-sekvens består av fire mulige molekyler, kalt C, A, G og T, og én mulig molekyltriplett er CAG. Om man bærer på et gen med for mange identiske CAG-tripletter etter hverandre i genet, er faren stor for å bli rammet av HS i ung alder og dø tidlig i livet. I nye studier er det tilhørende genet funnet i mange stadier i evolusjonshistoria. Første gang genet viste seg var for 550 millioner år siden, og genet finnes i alle dyrearter på jorda. Sykdommen HS kan være en tragisk følge av den evolusjonære prosessen, fordi mange CAG-tripletter på plass i genet ser ut til å være en forutsetning for et velutviklet nervesystem.

• Sudbø, Aasmund & Hamre, Børge (2019). Lysspreiing, lysabsorpsjon og to typar blåfarge på himmelen. Fra Fysikkens Verden.  ISSN 0015-9247.  81(2), s 30- 33 Vis sammendrag

  Himmelen er blå på grunn av lysspreiing frå molekyla i atmosfæren og at blått lys blir spreidd mest. Artikkelen forklarar at mot solnedgang trer ein annan effekt i funksjon som gir endring av nyansen av blåfargen.

• Sudbø, Aasmund & Røsjø, Bjarne (2019, 26. august). Naturvitenskapen, og Gud, er noe vi er blitt enige om. [Internett].  titan.uio.no. Vis sammendrag

  – Det naturvitenskapelige verdensbildet er noe som eksisterer fordi tilstrekkelig mange mennesker er blitt enige om det. Slik er det også med Gud, mener professor Aasmund Sudbø.

• Sudbø, Aasmund (2018). SI – det nye internasjonale einingssystemet. Fra Fysikkens Verden.  ISSN 0015-9247.  (1), s 14- 19 Vis sammendrag

  Det har nettopp kome forslag til revisjon av det internasjonale einingssystemet. Forslaget representerer ei omfattande ombygging av systemet.

• Gliss, Jonas; Stebel, Kerstin; Kylling, Arve & Sudbø, Aasmund (2017). Remote sensing of volcanic SO2 emissions using UV camera systems.
• Grepstad, Jon Olav; Gjessing, Jo; Angelskår, Hallvard; Skokic, Zeljko; Bakke, Thor; Herbjørnrød, Aina Kristin & Sudbø, Aasmund (2016). Design and Simulation of Efficient Narrowband Thermal Emitter with 3 µm wavelength. Vis sammendrag

  A low-power infrared source based on a silicon photonic-crystal membrane has been designed. Temperature distribution and reflection spectrum has been simulated. Large narrowband IR absorption is obtained with optimal material doping.

• Sudbø, Aasmund (2016). Ei laserhistorie - Tekniske framsteg kan ikkje planleggast. Fra Fysikkens Verden.  ISSN 0015-9247.  78(1), s 25- 26
• Sudbø, Aasmund & Snøfugl, Ingvil (2016, 01. februar). Norsk teknologi ble millionbutikk. [Internett]. Vis sammendrag

  I fjor kjøpe tyske Dräger SINTEF-knoppskuddet GasSecure for 500 millioner kroner. Idéen bak GasSecure var å lage en batteridrevet gassdetektor, som overfører data tråløst. Dette eksisterte ikke på markedet før det norske gründerselskapet utviklet denne teknologien i tett samarbeid med blant andre SINTEF. Klikk på videoen og se historien om GasSecure, som utviklet verdens første trådløse gassdetektor.

• Sudbø, Aasmund (2015). «Blålys» fra soloppgangens land (Nobelprisen i fysikk 2014). Vis sammendrag

  I 2014 ble nobelprisen i fysikk gitt «for oppfinnelsen av effektive blå lysdioder som har muliggjort lyssterke og energibesparende hvite lyskilder». Vi kjenner alle lysdioder (eng. Light Emitting Diode, LED) brukt i hjemmet i fjernkontroller for elektronikk av alle slag. Det usynlige infrarøde lyset som sendes ut er ideelt for formålet. Den tekniske utviklinga ga oss nokså snart også lysdioder som lyser rødt og gult, på tilsvarende måte som for infrarødt. Grønt og blått lys viste seg langt vanskeligere å realisere. Fortellingen om prisvinnere av nobelprisen i fysikk 2014 er en fantastisk historie om forskere som aldri gav opp når de fleste andre på området anså det som et håpløst prosjekt.

• Sudbø, Aasmund (2015). Ei laserhistorie: Store tekniske framsteg kan ikkje planleggast. Aftenposten Vitenskap.  ISSN 2464-3033.
• Sudbø, Aasmund (2015). Lysleiande fibrar skapte Internett. Fra Fysikkens Verden.  ISSN 0015-9247.  77(2), s 37- 43
• Sudbø, Aasmund (2015). Lysleiande fibrar: Det som skapte Internett. Vis sammendrag

  Lysleiande fibrar har gjort det nesten gratis å sende informasjon verda rundt. Denne artikkelen gjev ei oversikt over verkemåten til lysleiarane som er kjernen i Internett, og dei viktigaste stega i utviklinga av desse lysleiarane. Vi skal også sjå på utsiktene til vidare teknisk utvikling på bakgrunn av det som er kjent om fysikken i slike lysleiarar.

• Sudbø, Aasmund (2015). Nå kan vi se enkeltmolekyler i et lysmikroskop. Vis sammendrag

  I 2014 ble nobelprisen i kjemi gitt «for utvikling av fluorescensmikroskopi med superoppløsning». Bakgrunnen er den begrensningen som ligger i et vanlig mikroskop, at bildet av en liten nok kilde vil være en flekk med en diameter som er bestemt av lysbølgelengden og ikke av diameteren til lyskilden. Om diameteren på kilden er mindre enn en halv lysbølgelengde er diameteren til den tilhørende flekken i bildet nesten uavhengig av kildediameteren. Dersom vi sikrer oss at vi har bare en lysflekk i bildet kan vi bruke datamaskin til å bestemme posisjonen til sentrum i flekken med en usikkerhet som er langt mindre enn diameteren på flekken. Posisjonen til kilden blir tilsvarende nøyaktig bestemt. De tre vinnere av nobelprisen i kjemi i 2014 har utnyttet denne ideen til å utvikle lysmikroskop der vi kan ta bilder av enkeltmolekyler i levende celler og vev med en romlig oppløsning langt under en halv lysbølgelengde.

• Sudbø, Aasmund (2015). Universet er kaldt, og det kan vi utnytte.
• Sudbø, Aasmund & Grepstad, Jon Olav (2015). Detecting single particles using guided-resonance modes in photonic crystal membranes with finite area.
• Grepstad, Jon Olav; Greve, Martin Møller; Holst, Bodil; Johansen, Ib-Rune; Solgaard, Olav & Sudbø, Aasmund (2014). Finite-size limitations on the strength of guided resonances in 2D photonic crystals.
• Grepstad, Jon Olav; Greve, Martin Møller; Johansen, Ib-Rune; Solgaard, Olav & Sudbø, Aasmund (2014). Photonic crystals designed for optical biosensing, applied to detect single nano-particles.
• Marstein, Erik Stensrud; Gjessing, Jo; Thorstensen, Jostein Bruun; Haugan, Einar; Selj, Josefine Helene; Foss, Sean Erik & Sudbø, Aasmund (2014). Light trapping nanostructures for ultrathin crystalline silicon solar cells.
• Grepstad, Jon Olav; Kaspar, Peter; Solgaard, Olav; Johansen, Ib-Rune & Sudbø, Aasmund (2013). Single nano-particle sensing exploiting crossed polarizers to improve the signal-to-noise ratio.
• Grepstad, Jon Olav; Kaspar, Peter; Solgaard, Olav; Johansen, Ib-Rune & Sudbø, Aasmund (2013). Single nano-particle sensing exploiting crossed polarizers to improve the signal-to-noise ratio.
• Marstein, Erik Stensrud & Sudbø, Aasmund (2013, 30. april). Next-Gen Solar Cells Trap Sunlight with Microbeads.  Photonics Spectra Magazine.
• Sudbø, Aasmund & Marstein, Erik Stensrud (2013, 29. januar). Lurer sollyset med mikrosmå kuler. [Internett].  Apollon. Vis sammendrag

  Om fem til sju år er solcellene blitt mye billigere – og bare en tjuendedel så tjukke som dagens solceller. Trikset er å lure sollyset med mikrokuler. Nanoforskere utvikler nå neste generasjons solceller, som skal bli tjue ganger tynnere enn dagens solceller. Over 90 prosent av dagens strøm fra solcelle-panel er laget av 200 mikrometer tykke silisiumplater. Det lages flere milliarder hvert år. Problemet er det store forbruket av silisium, hele fem gram silisium per watt.

• Thorstensen, Jostein Bruun; Foss, Sean Erik; Sudbø, Aasmund Sveinung & Marstein, Erik Stensrud (2013). Laser processing for thin and highly efficient silicon solar cells. Series of dissertations submitted to the Faculty of Mathematics and Natural Sciences, University of Oslo.. 1367.
• Grepstad, Jon Olav; Kaspar, Peter; Solgaard, Olav; Johansen, Ib-Rune & Sudbø, Aasmund (2012). Enhanced scattering from nano-particles trapped in photonic crystal membranes.
• Gjessing, Jo; Marstein, Erik Stensrud; einar, haugan; Håvard, Granlund & Sudbø, Aasmund (2012). Photonic Crystals for Light Trapping in Solar Cells, invited talk presented by A.S. Sudbø.
• Gjessing, Jo; Marstein, Erik Stensrud; Haugan, Einar; Granlund, Håvard & Sudbø, Aasmund (2012). Photonic crystals for light trapping in solar cells.
• Grepstad, Jon Olav; Kaspar, Peter; Johansen, Ib-Rune; Skaar, Johannes; Sudbø, Aasmund & Solgaard, Olav (2012). Optical detection of single biomolecules using photonic-crystal membranes.
• Grepstad, Jon Olav; Kaspar, Peter; Solgaard, Olav; Johansen, Ib-Rune & Sudbø, Aasmund (2012). Gain in Rayleigh scattering from nanoparticles trapped in photonic crystal membranes.
• Grepstad, Jon Olav; Kaspar, Peter; Solgaard, Olav; Johansen, Ib-Rune & Sudbø, Aasmund (2012). Optical detection of single biomolecules using photonic crystal membranes.
• Grepstad, Jon Olav; Kaspar, Peter; Solgaard, Olav; Johansen, Ib-Rune & Sudbø, Aasmund (2012). Optical imaging system designed for biosensing using a photonic crystal membrane to detect nanoparticles.
• Marstein, Erik Stensrud; Selj, Josefine Helene; Gjessing, Jo; Haug, Hallvard & Sudbø, Aasmund (2012). Light Management in Thin Crystalline Silicon Solar Cells. Vis sammendrag

  In order to reduce the costs of solar cells, there is a strong drive towards the use of thinner absorber materials. Crystalline silicon materials have already proven highly attractive as absorbers in mass produced, low cost and efficient solar cells. However as absorbers become thinner, crystalline silicon solar cells increasingly suffer from optical losses related to transmission, which again lead to losses in short circuit current density and efficiency. In this work, recent developments of structures for managing light in co-planar, ultrathin crystalline silicon substrates made in our group will be presented. We will show that the light trapping can be dramatically enhanced in ultrathin crystalline silicon wafers by incorporating periodic nanostructures on a solar cell rear side covered with a surface-passivating dielectric and metal mirror. To allow for simplified module and solar cell processing with such structures, we have aimed at developing a co-planar solar cell structure. Unfortunately, without proper measures, the resulting increases in front side reflectance will cancel out any gain in light trapping. We will therefore also show that a multilayer thin film anti-reflection coating (ARC) structure can sufficiently reduce front side reflection in a solar cell and module environment.

• Sudbø, Aasmund (2012). Optical Antennas Made of Silicon.
• Gjessing, Jo; Sudbø, Aasmund Sveinung & Marstein, Erik Stensrud (2011). Comparison of light trapping in diffractive and random pyramidal structures.
• Gjessing, Jo; Sudbø, Aasmund & Marstein, Erik Stensrud (2011). Nanostructured back-side reflector for thin silicon solar cells.
• Grepstad, Jon Olav; Due-Hansen, Jon; Johansen, Ib-Rune; Borch, Morten; Kaspar, Peter; Furuberg, Liv; Skaar, Johannes; Sudbø, Aasmund Sveinung & Solgaard, Olav (2011). Umiddelbar diagnose i 2020.
• Grepstad, Jon Olav; Kaspar, Peter; Due-Hansen, Jon; Johansen, Ib-Rune; Borch, Morten; Furuberg, Liv; Skaar, Johannes; Sudbø, Aasmund Sveinung & Solgaard, Olav (2011). System for optical characterization of photonic crystal membranes - designed for biological sensing with single molecule sensitivity.
• Gjessing, Jo; Marstein, Erik Stensrud & Sudbø, Aasmund Sveinung (2010). A novel broad-band back-side reflector for thin silicon solar cells.
• Gjessing, Jo; Sudbø, Aasmund Sveinung & Marstein, Erik Stensrud (2010). 2-D Blazed Grating for Light Trapping in Thin Silicon Solar Cells.
• Grepstad, Jon Olav; Johansen, Ib-Rune; Borch, Morten; Furuberg, Liv; Skaar, Johannes; Sudbø, Aasmund Sveinung & Solgaard, Olav (2010). Photonic crystal based biosensing platform for single molecule detection.
• Sudbø, Aasmund Sveinung; Angelskår, Hallvard; Johansen, Ib-Rune; Lacolle, Matthieu Jean P; Løvhaugen, Odd & Sagberg, Håkon (2010). Nanophotonics Everywhere.
• Angelskår, Hallvard; Bouquet, Gregory; Johansen, Ib-Rune; Lacolle, Matthieu Jean P; Løvhaugen, Odd; Sagberg, Håkon & Sudbø, Aasmund Sveinung (2009). Nanophotonics for Spectroscopy Everywhere, Bouquet, G., Johansen, I.R., Lacolle, M., Løvhaugen, O., Sagberg,H., Sudbø, A.S.,.
• Angelskår, Hallvard; Johansen, Ib-Rune; Lacolle, Matthieu Jean P & Sudbø, Aasmund Sveinung (2009). Spectral uniformity of diffractive optical elements for spectroscopy.
• Gjessing, Jo; Marstein, Erik Stensrud & Sudbø, Aasmund Sveinung (2009). Modelling of back-side diffraction grating applied for light trapping in solar cells.
• Gjessing, Jo; Marstein, Erik Stensrud & Sudbø, Aasmund Sveinung (2009). Modelling of back-side diffraction gratings applied for light trapping in silicon solar cells.
• Gjessing, Jo; Marstein, Erik Stensrud & Sudbø, Aasmund Sveinung (2009). Modelling of back-side diffraction gratings applied for light trapping in solar cell.
• Gjessing, Jo; Marstein, Erik Stensrud & Sudbø, Aasmund Sveinung (2009). Modelling of light trapping in thin silicon solar cells with back-side dielectric diffraction grating.
• Hadzialic, Sanja; Kim, Sora; Sudbø, Aasmund Sveinung & Solgaard, Olav (2009). Photonic Crystal Slabs for Micro Electro‐Mechanical Systems.
• Hadzialic, Sanja; Kim, Sora; Sudbø, Aasmund Sveinung & Solgaard, Olav (2009). Photonic Crystal Slabs for Micro-Electromechanical Systems.
• Sudbø, Aasmund Sveinung (2009). Gjest i FFV. Fra Fysikkens Verden.  ISSN 0015-9247.  (4) Vis sammendrag

  Nobelprisen i fysikk 2009

• Sudbø, Aasmund Sveinung (2009). Integrated Optofluidics.
• Sudbø, Aasmund Sveinung; Angelskår, Hallvard; Bouquet, Gregory; Johansen, Ib-Rune; Lacolle, Matthieu Jean P; Løvhaugen, Odd & Sagberg, Håkon (2008). Nanophotonics for Microsystems Everywhere.
• Angelskår, Hallvard; Bouquet, Grégory; Johansen, Ib-Rune; Lacolle, Matthieu Jean P; Løvhaugen, Odd; Sagberg, Håkon & Sudbø, Aasmund (2008). Characterization and polarization resolved simulation of diffractive optical elements. Fulltekst i vitenarkiv. Vis sammendrag

  We present our activity on the characterization and simulation of diffractive optical elements (DOEs) for near infrared spectroscopy. The DOE surface is designed to direct and focus light of a limited set of wavelengths onto a detector. In order to perform this, the surface pattern has a complicated structure and varies significantly over the element. This leads to a variation in the diffraction efficiency if the incident light only illuminates certain parts of the DOE. For the use of a DOE in a spectrometer, it is for some applications important that the local diffraction efficiency of each wavelength component relative to the others is as uniform as possible over the DOE. Otherwise, the spectroscopic measurement can become unreliable. A measurement setup was built at SINTEF to characterize the DOEs. This setup uses a movable aperture in front of the DOE, so that it is possible to measure the diffraction efficiency in different positions on the DOE. The simulations were carried out using the PCGrate software [1], which computes the diffraction efficiency for a periodic diffraction grating, employing full vectorial representation of the optical field. We carried out the simulations for one wavelength and position at a time, modeling the DOE surface by a perfectly periodic diffraction grating, with a period and an orientation designed to yield a surface with the same performance as the fabricated DOE. This yields a simple model that gives variations of local diffraction efficiency of the same order of magnitude as the measurements.

• Basu Mallick, Shrestha; Kim, Sora; Hadzialic, Sanja; Sudbø, Aasmund Sveinung & Solgaard, Olav (2008). Double-layered monolithic silicon photonic crystals. Vis sammendrag

  Double-layered, self-aligned, silicon photonic crystals are fabricated using directional and isotropic etches - a potential step towards 3D PCs. One structure shows sharper resonances compared to corresponding single layer structure. Another shows high, broadband reflectivity.

• Blad, Jakob & Sudbø, Aasmund Sveinung (2008). Numerical method for systematic search for modes in a two-dimensional photonic crystal.
• Gjessing, Jo; Marstein, Erik Stensrud & Sudbø, Aasmund Sveinung (2008). Photonic crystals applied for light trapping in solar cells.
• Hadzialic, Sanja; Kim, Sora; Mallick, Shrestha Basu; Sudbø, Aasmund Sveinung & Solgaard, Olav (2008). Monolithic Photonic Crystals.
• Hadzialic, Sanja; Kim, Sora; Mallick, Shrestha Basu; Sudbø, Aasmund Sveinung & Solgaard, Olav (2008). Monolithic Photonic Crystals.
• Sudbø, Aasmund Sveinung (2008). Design and Modelling of Photonic Crystal Films,.
• Sudbø, Aasmund Sveinung (2008). Fotoniske krystallar for sensorar.
• Sudbø, Aasmund Sveinung; Hadzialic, Sanja; Blad, Jakob; Kim, Sora; Mallick, Shrestha Basu & Solgaard, Olav (2008). Photonic Crystal Films. Vis sammendrag

  We have studied photonic crystal (PC) films in the form of planar silicon membranes suspended in air, and report on design, analysis, fabrication and optical characterization of such films. We review the optical properties of PC films, and some of their demonstrated device applications. We report our progress in developing modal expansion using two-dimensional Bloch waves as a method to analyze the guided modes and resonances of PC films. Single-layer PC films can be used as broadband low-loss mirrors, and planar double-layer PC films can be used as frequency-dependent mirrors, where the spectral response can be micromechanically tuned. We have fabricated and characterized broadband mirrors experimentally [1], [2], and we report on reflectance and transmittance spectra that we have measured. We have also fabricated sensors based on PC films with optical read-out [3], and we report on the sensor performance we have measured.

• Angelskår, Hallvard; Johansen, Ib-Rune & Sudbø, Aasmund Sveinung (2007). Diffractive Optical Elements for Spectroscopy.
• Bjørnstad, Steinar; Nord, Martin; Eriksen, Lars Erik; Tuft, Vegard; Hjelme, Dag Roar; Stol, Norvald; Kimsås, Andreas & Sudbø, Aasmund Sveinung (2007). Demonstration and analysis of TV- and data transport in the OpMiGua hybrid circuit/packet switched network testbed.
• Bjørnstad, Steinar; Nord, Martin; Eriksen, Lars Erik; Tuft, Vegard Larsen; Hjelme, Dag Roar; Stol, Norvald; Kimsas, Andreas & Sudbø, Aasmund (2007). Demonstration and analysis of TV- and data transport in the OpMiGua hybrid circuit/packet switched network testbed.
• Blad, Jakob & Sudbø, Aasmund Sveinung (2007). Numerical method for a systematic search for modes in a two-dimensional photonic crystal.
• Hadzialic, Sanja; Kim, Sora; Mallick, Shrestha Basu; Sudbø, Aasmund Sveinung & Solgaard, Olav (2007). Monolithic Photonic Crystals.
• Hadzialic, Sanja; Kim, Sora; Sudbø, Aasmund Sveinung & Solgaard, Olav (2007). Displacement Sensing with a Mechanically Tunable Photonic Crystal.
• Kim, Sora; Hadzialic, Sanja; Sudbø, Aasmund Sveinung & Solgaard, Olav (2007). Single-film Broadband Photonic Crystal Micro-mirror with Large Angular Range and Low Polarization Dependence.
• Sudbø, Aasmund Sveinung (2007). Fotoniske krystallar for optisk spektroskopi.
• Sudbø, Aasmund Sveinung (2007). Fundamentals of Photonic Crystal Films.
• Sudbø, Aasmund Sveinung (2007). Photonic Crystal Slabs for Optical Mirrors and Filters.
• Lacolle, Matthieu Jean P; Sagberg, Håkon; Johansen, Ib-Rune; Løvhaugen, Odd; Sudbø, Aasmund Sveinung & Solgaard, Olav (2006). Micromechanical diffractive optical filters for spectroscopy.
• Lacolle, Matthieu Jean P; Sudbø, Aasmund Sveinung & Johansen, Ib-Rune (2006). Optical spectral filtering with segmented diffractive optical elements. Dissertation for the Degree Dr. Philos. ISSN 1501-7710. 552. Vis sammendrag

  This thesis presents a study of optical spectral filtering with segmented Diffractive Optical Elements (DOEs). Instead of moving a DOE as a whole, as is done with a scanning monochromator, it is possible to segment a DOE in several parts that can be displaced individually. This principle gives much more freedom in the way the filter transmission can be controlled. However, typical dimensions of DOEs and the accuracy in the displacements require a level of miniaturisation that was not achievable at a reasonable cost. The development of micro-technologies has changed this context, making possible the fabrication of both the DOE and the actuation mechanism on a single micro-mechanical chip. The present work describes in detail several implementations of micro-mechanical segmented DOE filters, which we believe to be especially well-suited to the synthesis of spectral filters with arbitrary transmissions. The spectral transmission of those DOE filters is derived, using the scalar diffraction theory. We also study several algorithms that give the positions of the segments, so that the synthetic filter transmission matches a target. The performances of these algorithms are assessed both theoretically and with computer simulations. Based on those results, we compare DOE filters to other types of optical filters with controllable or adjustable spectral transmission, and show that segmented DOE filters have inherent advantages and limitations. We came to the conclusion that segmented DOE filters are especially well-suited to some tasks in spectroscopy, and to this effect we fabricated a prototype of a micro-mechanical diffractive Fresnel lens. This work encompasses the fabrication of the prototype, as well as an experimental characterisation that has a value of proof of principle.

• Tuft, Vegard; Bjørnstad, Steinar; Sudbø, Aasmund Sveinung & Hjelme, Dag Roar (2006). Using the state of polarization in a hybrid optical network, paper W46 at the conference ‘,’ 14-16 June 2006,.
• Arisholm, Gunnar & Sudbø, Aasmund Sveinung (ed.) (2006). Northern Optics 2006 Conference Technical Digest.
• Blad, Jakob; Hadzialic, Sanja; Solgaard, Olav; Sudbø, Aasmund Sveinung; Grujic, Katarina; Wilkinson, JS; Hellesø, Olav Gaute & Hole, JP (2006). Nanostrukturar for optikk. Vis sammendrag

  Formål: Realisere optiske funksjonar eller komponentar vha nanostrukturar. Bygge opp eit norsk fagmiljø som kan heile prosessen med design, modellering, framstilling og karakterisering av slike strukturar. To delaktivitetar: Nye typer justerbare optiske speglar og filter(sk 2D fotoniske krystallar) Lys til å flytta mikro- og nanopartiklar

• Blad, Jakob; Sudbø, Aasmund Sveinung & Solgaard, Olav (2006). Photonic crystals as angle-insensitive broadband mirrors, paper W51 at the conference ‘,’ 14-16 June 2006,.
• Clausen, Ingelin; Sveen, Ola; Sudbø, Aasmund Sveinung & Lundar, Trygve (2006). An implanted micro electro mechanical system for permanent measurement of human brain pressure. Dissertation for the Degree Dr. Philos. ISSN 1501-7710. 525. Vis sammendrag

  1.1 The aim of the work The aim of the work presented in this thesis has been to: · establish a measurement setup for characterization of micromachined pressure sensors · characterize an already fabricated pressure sensor prototype · evaluate the reliability of the sensor · propose and evaluate packaging solutions · perform in-vivo testing as “proof of concept”

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