Hur lär barn om väder?

Jag har velat ta reda på hur det är att arbeta med det naturvetenskapliga ämnet väder med åttaåringar. Mina utgångspunkter har varit teorier om lärande, experimentets roll för lärande och lärarens roll för lärandet. Den tematiska arbetsformen har bildat ramen för undersökning om hur barn lär om väder. Jag har intervjuat eleverna i smågrupper och det har kommit fram intressanta reflektioner från eleverna. Eleverna har uttryckt att de har lärt sig nya saker om väder. De har också uttryckt att gamla föreställningar har förändrats. Det finns en utbredd rädsla och forskningen är eftersatt kring barns lärande om naturvetenskap. Jag har i min undersökning upplevt att åttaåringar kan förstå komplexa väderfenomen, med hjälp av olika pedagogiska inlärningsstilar

Media 2: Porous silicon integrated Mach-Zehnder interferometer waveguide for biological and chemical sensing

Originally published in Optics Express on 26 August 2013 (oe-21-17-19488

Media 1: Terahertz nonlinear conduction and absorption saturation in silicon waveguides

Originally published in Optica on 20 June 2015 (optica-2-6-553

Media 3: Terahertz surface plasmon polaritons on a semiconductor surface structured with periodic V-grooves

Originally published in Optics Express on 25 March 2013 (oe-21-6-7041

Media 1: Terahertz surface plasmon polaritons on a semiconductor surface structured with periodic V-grooves

Originally published in Optics Express on 25 March 2013 (oe-21-6-7041

Media 4: Terahertz surface plasmon polaritons on a semiconductor surface structured with periodic V-grooves

Originally published in Optics Express on 25 March 2013 (oe-21-6-7041

Media 2: Terahertz surface plasmon polaritons on a semiconductor surface structured with periodic V-grooves

Originally published in Optics Express on 25 March 2013 (oe-21-6-7041

Nonlinear Terahertz Absorption of Graphene Plasmons

Subwavelength graphene structures support localized plasmonic resonances in the terahertz and mid-infrared spectral regimes. The strong field confinement at the resonant frequency is predicted to significantly enhance the light-graphene interaction, which could enable nonlinear optics at low intensity in atomically thin, subwavelength devices. To date, the nonlinear response of graphene plasmons and their energy loss dynamics have not been experimentally studied. We measure and theoretically model the terahertz nonlinear response and energy relaxation dynamics of plasmons in graphene nanoribbons. We employ a terahertz pump–terahertz probe technique at the plasmon frequency and observe a strong saturation of plasmon absorption followed by a 10 ps relaxation time. The observed nonlinearity is enhanced by 2 orders of magnitude compared to unpatterned graphene with no plasmon resonance. We further present a thermal model for the nonlinear plasmonic absorption that supports the experimental results. The model shows that the observed strong linearity is caused by an unexpected red shift of plasmon resonance together with a broadening and weakening of the resonance caused by the transient increase in electron temperature. The model further predicts that even greater resonant enhancement of the nonlinear response can be expected in high-mobility graphene, suggesting that nonlinear graphene plasmonic devices could be promising candidates for nonlinear optical processing

Plasmon-Enhanced Terahertz Photodetection in Graphene

We report a large area terahertz detector utilizing a tunable plasmonic resonance in subwavelength graphene microribbons on SiC(0001) to increase the absorption efficiency. By tailoring the orientation of the graphene ribbons with respect to an array of subwavelength bimetallic electrodes, we achieve a condition in which the plasmonic mode can be efficiently excited by an incident wave polarized perpendicular to the electrode array, while the resulting photothermal voltage can be observed between the outermost electrodes

Plasmon-Enhanced Terahertz Photodetection in Graphene

We report a large area terahertz detector utilizing a tunable plasmonic resonance in subwavelength graphene microribbons on SiC(0001) to increase the absorption efficiency. By tailoring the orientation of the graphene ribbons with respect to an array of subwavelength bimetallic electrodes, we achieve a condition in which the plasmonic mode can be efficiently excited by an incident wave polarized perpendicular to the electrode array, while the resulting photothermal voltage can be observed between the outermost electrodes