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| 2. |
- Alkeskjold, T., et al.
(author)
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Optically tunable bandgap fiber
- 2005
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In: Optics Photonics News, special edition "Optics in 2005". ; 16:12, s. 36-
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Journal article (other academic/artistic)
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| 3. |
- Alkeskjold, T. T., et al.
(author)
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Highly tunable large-core single-mode liquid-crystal photonic bandgap fiber
- 2006
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In: Applied Optics. - 1539-4522. ; 45:10, s. 2261-2264
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Journal article (peer-reviewed)abstract
- We demonstrate a highly tunable photonic bandgap fiber, which has a large-core diameter of 25 μm and an effective mode area of 440 μm 2. The tunability is achieved by infiltrating the air holes of a photonic crystal fiber with an optimized liquid-crystal mixture having a large temperature gradient of the refractive indices at room temperature. A bandgap tuning sensitivity of 27 nm/°C is achieved at room temperature. The insertion loss is estimated to be less than 0.5 dB and caused mainly by coupling loss between the index-guided mode and the bandgap-guided mode.
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| 4. |
- Pedersen, M O, et al.
(author)
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Diffusion of N adatoms on the Fe(100) surface
- 2000
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 84:21, s. 4898-4901
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Journal article (peer-reviewed)abstract
- The diffusion of individual N adatoms on Fe(100) has been studied using scanning tunneling microscopy and ab initio density functional theory (DFT) calculations. The measured diffusion barrier for isolated N adatoms is E-d = (0.92 +/- 0.04) eV, with a prefactor of nu(0) = 4.3 x 10(12) s(-1), which is in quantitative agreement with the DFT calculations. Thr; diffusion is strongly coupled to lattice distortions. and. as a consequence, the presence of other N adatoms introduces an anisotropy in the diffusion. Based on experimentally determined values of the diffusion barriers and adsorbate-adsorbate: interactions, the potential energy surface experienced by a N adatom is determined.
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| 5. |
- Li, W X, et al.
(author)
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Oxidation of Pt(110)
- 2004
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 93:14, s. 146104-
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Journal article (peer-reviewed)abstract
- Using scanning tunneling microscopy and temperature programed desorption we investigate the Pt(110) surface under strongly oxidizing conditions involving either high-pressure O-2 or atomic oxygen exposure. At low temperatures, only disordered Pt oxide structures are observed. After annealing ordered surface oxide islands are observed to coexist with a highly stable reconstructed (12x2)-O chemisorption structure. From density functional theory calculations a model for the surface oxide phase is revealed. The phase is found to be metastable, and its presence is explained in terms of stabilizing defects in the chemisorption layer and reduced Pt mobility.
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