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| 2. |
- Arnold, C. L., et al.
(författare)
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The ELI-ALPS secondary sources : A getaway to scientific excellence
- 2013
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Ingår i: 2013 Conference on Lasers and Electro-Optics, CLEO 2013. - 9781557529725 ; 2013
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Konferensbidrag (refereegranskat)abstract
- The essence of ELI-ALPS, the laser driven secondary sources ranging from X-ray and X-UV to THz with duration as short as tens of attoseconds, are designed to be available for users from 2016.
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| 3. |
- Heyl, C. M., et al.
(författare)
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Noncollinear optical gating - A method for intra-cavity single attosecond pulse generation?
- 2019
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Ingår i: Proceedings 2015 European Conference on Lasers and Electro-Optics - European Quantum Electronics Conference, CLEO/Europe-EQEC 2015. - 9781467374750
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Konferensbidrag (refereegranskat)abstract
- The process of high-order harmonic generation requires laser intensities around 1014 W/cm2, most easily reached with laser pulses of high energy, thus implicitly limiting the repetition rate of attosecond sources. A route towards multi-MHz attosecond sources relies on HHG inside a passive enhancement cavity [1]. Although successfully demonstrated for attosecond pulse trains, the generation of single attosecond pulses (SAPs) inside a cavity remains an unsolved challenge, mainly limited by dispersion management and out-coupling problems. We recently proposed a new gating concept for SAP generation [2], noncollinear optical gating (NOG) which has the potential to facilitate SAP gating and efficient out-coupling at once. Similar to the recently introduced attosecond lighthouse [3] NOG employs attosecond angular streaking [4] and combines this concept with noncollinear HHG, proposed earlier [5] as out-coupling method for intra cavity HHG.
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| 4. |
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| 5. |
- Rocca, J. J., et al.
(författare)
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Compact Soft X-ray Lasers for Imaging, Material Processing, and Characterization at the Nanoscale
- 2007
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Ingår i: 32nd IEEE/CPMT International Electronic Manufacturing Technology Symposium. - 9781424413355 ; , s. 72-73
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Konferensbidrag (refereegranskat)abstract
- As manufacturing of devices advances into the nanoscale, critical feature sizes have rapidly shrunk to below the wavelength of visible light. These advances in nanotechnology have created a need to develop better ways of accessing the nanoworld. The extreme ultraviolet (EUV)/ soft x-ray (SXR) region of the spectrum provides an opportunity to use coherent light at wavelengths that are 10- to 100-times shorter than visible light, at 1 to 100 nm. Given the diffraction limit in imaging resolution, these wavelengths allow us to "see" smaller features and "write" smaller patterns than would be possible with visible light. We have developed compact laser-pumped and discharge-pumped lasers operating at wavelengths of λ=13.2 nm [1] and λ=46.9 nm [2] respectively, and have used them in the demonstration of nanoscale full field imaging [3,4], nanopatterning [5], and nanoscale laser ablation [6]. The high brightness and short wavelength output from these lasers when combined with specialized EUV/SXR optics, offer unique opportunities for the implementation of table-top imaging, patterning and metrology tools with superior spatial resolution for applications in nanoscience and nanotechnology. Using these new compact short wavelength lasers we have built two microscopes, using λ=46.9 nm or λ=l 3.2 nm laser illumination. The compact λ=46.9 nm microscope (Fig. 1a and lb) condenses the light using a multilayer coated Schwarzschild mirror, and images the test object using a diffractive zone plate lens. The spatial resolution of this microscopes was assessed by imaging test samples consisting of dense line gratings of half-periods ranging from 200 down to 35 nm. Figure 2(a) and (b) show images of a 100 nm and 70 nm half-period gratings obtained with the λ =46.9 nm microscope. The lineout in the image of the 70 nm lines shows a modulation of ∼30% indicating that the features are fully resolved according to the Rayleigh criterion. By rearranging the optics, the λ=46.9 nm microscope can also image surfaces. An image of fully resolved dense metal lines, with half-period of 170 nm, patterned on the silicon wafer is shown in Figure 2 (c). The shorter wavelength λ= 3.2 nm microscope uses all zone plate optics to render images of transmissive test patterns with increased spatial resolution . An image of fully resolved 50 nm half-period dense lines acquired with a 20 seconds exposure is shown in Figure 2(d). From images like this one, the spatial resolution of the λ=13.2 nm table-top microscope was determined to be better than 38 nm [3]. The high coherence of these short wavelength lasers also allows for the printing of arrays of nanoscale features using interferometric lithography. We have demonstrated combined a λ=46.9 nm capillary discharge laser and a Lloyd's mirror to print arrays of cone-shaped nano-dots with ∼ 58 nm FWHM diameter (Fig 3a) [5]. The same arrangement was used to print arrays of nano-holes 120 nm FWHM and 100 nm in depth over areas in excess of 500 × 500 μm2 in different photoresists using exposure times as short as 80 s. Larger area patterns can be readily printed using precision translation stages and multiple exposures by overlay superposition. The ability to focus SXL laser light into near diffraction-limited spots also opens the possibility to develop new types of nanoprobes. We have demonstrated ablation of sub-100 nm diameter holes by directly focusing the output of a λ=46.9 nm laser onto a sample with a zone plate lens. Figure 3(b) shows an AFM image of a 82 nm diameter crater obtained ablating a 500 nm thick PMMA layer with a single laser shot. The holes were observed to have very clean walls and high reproducibility. We have recently added the capability to spectroscopically analyze the light emitted from the plasma created during the ablation, opening the possibility to develop analytic nanoprobles. All of these results illustrate the capabilities of compact short wavelength lasers for nanotechnology applications.
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| 6. |
- Albert, F. W., et al.
(författare)
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Targeted resequencing of a genomic region influencing tameness and aggression reveals multiple signals of positive selection
- 2011
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Ingår i: Heredity. - : Springer Science and Business Media LLC. - 0018-067X .- 1365-2540. ; 107:3, s. 205-214
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Tidskriftsartikel (refereegranskat)abstract
- The identification of the causative genetic variants in quantitative trait loci (QTL) influencing phenotypic traits is challenging, especially in crosses between outbred strains. We have previously identified several QTL influencing tameness and aggression in a cross between two lines of wild-derived, outbred rats (Rattus norvegicus) selected for their behavior towards humans. Here, we use targeted sequence capture and massively parallel sequencing of all genes in the strongest QTL in the founder animals of the cross. We identify many novel sequence variants, several of which are potentially functionally relevant. The QTL contains several regions where either the tame or the aggressive founders contain no sequence variation, and two regions where alternative haplotypes are fixed between the founders. A re-analysis of the QTL signal showed that the causative site is likely to be fixed among the tame founder animals, but that several causative alleles may segregate among the aggressive founder animals. Using a formal test for the detection of positive selection, we find 10 putative positively selected regions, some of which are close to genes known to influence behavior. Together, these results show that the QTL is probably not caused by a single selected site, but may instead represent the joint effects of several sites that were targets of polygenic selection.
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| 7. |
- Barreda, V. D., et al.
(författare)
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Eocene Patagonia Fossils of the Daisy Family
- 2010
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 329:5999, s. 1621-1621
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Tidskriftsartikel (refereegranskat)abstract
- Fossil evidence suggests that daisies and sunflowers may have originated in South America more than 47 million years ago.
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| 8. |
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| 9. |
- Menoni, C. S., et al.
(författare)
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Nanometer-scale imaging and ablation with Extreme Ultraviolet lasers
- 2007
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Ingår i: 2007 CONFERENCE ON LASERS & ELECTRO-OPTICS/QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE (CLEO/QELS 2007), VOLS 1-5. - 9781424435906 ; , s. 1401-1402
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Konferensbidrag (refereegranskat)abstract
- The short wavelength and high brightness of compact extreme ultraviolet lasers is shown to enable the development of microscopes with spatial resolution of tens of nanometers and new types of nanoprobes.
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| 10. |
- Brizuela, F., et al.
(författare)
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High resolution full-field imaging of nanostructures using compact extreme ultraviolet lasers
- 2009
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Ingår i: 9TH INTERNATIONAL CONFERENCE ON X-RAY MICROSCOPY. - : IOP Publishing.
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Konferensbidrag (refereegranskat)abstract
- Recent advances in the development of high peak brightness table-top extreme ultraviolet (EUV) and soft x-ray (SRX) lasers have opened new opportunities for the demonstration of compact full-field EUV/SXR microscopes capable of capturing images with short exposures down to a single laser shot. We demonstrate the practical application of table-top zone plate EUV microscopes that can image nanostructures with a spatial resolution of 54 nm and below and exposure times as short as 1.2 ns, the duration of a single laser shot.
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