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- Urquiza-González, M., et al.
(författare)
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Benchmark evaluation for a single frequency continuous wave OPO seeded pulsed dye amplifier for high-resolution laser spectroscopy
- 2023
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. - 9781510659032
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Konferensbidrag (refereegranskat)abstract
- The study of the atomic spectrum via resonant laser excitation provides access to underlying effects caused by the nuclear structure, which is of special interest in short-lived radioisotopes produced at Isotope Separator On-Line (ISOL) facilities. Current implementations of resonant laser ionization techniques often limit the extraction of the nuclear observables due to the low spectral resolution of the pulsed laser systems deployed. Several high-resolution spectroscopy techniques demand spectral widths in the order of hundreds of MHz and below. A proven solution to reduce this linewidth is the pulsed amplification of a narrow-band continuous wave (cw) laser. This work presents the demonstration of a pulsed dye amplifier seeded by a commercially available cw Optical Parametric Oscillator (OPO). The performance of this system was compared with competing setups using a cw dye laser seed source as well as a frequency mixing technique using a combination of an injection-locked titanium:sapphire (Ti:Sa) and a Nd:YVO4 laser. Spectral bandwidths of the systems were measured using a high finesse Fabry-Perot Interferometer, resulting in comparable optical linewidths between 140 to 156 MHz at a wavelength of 328 nm for the different laser setups. Suitability for on-line experiments was validated by performing high-resolution spectroscopy of radioactive silver isotopes in the Collinear Resonance Ionization Spectroscopy (CRIS) experiment at the Isotope Separator On-Line Device (ISOLDE), at the European Organization for Nuclear Research (CERN). The quality of the hyperfine spectra was similar for the dye and the OPO seed and the deduced hyperfine splitting was in good agreement with literature, while the frequency mixing technique exhibited less precise results attributed to the frequency instabilities and mode-hops of the single-mode Nd:YVO4 laser.
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| 3. |
- Syväjärvi, Mikael, et al.
(författare)
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Fluorescent SiC as a new material for white LEDs
- 2012
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Ingår i: Physica scripta. T. - 0281-1847 .- 0031-8949 .- 1402-4896. ; T148, s. 014002-
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Tidskriftsartikel (refereegranskat)abstract
- Current III–V-based white light-emitting diodes (LEDs) are available. However, their yellow phosphor converter is not efficient at high currents and includes rare-earth metals, which are becoming scarce. In this paper, we present the growth of a fluorescent silicon carbide material that is obtained by nitrogen and boron doping and that acts as a converter using a semiconductor. The luminescence is obtained at room temperature, and shows a broad luminescence band characteristic of donor-to-acceptor pair recombination. Photoluminescence intensities and carrier lifetimes reflect a sensitivity to nitrogen and boron concentrations. For an LED device, the growth needs to apply low-off-axis substrates. We show by ultra-high-resolution analytical transmission electron microscopy using aberration-corrected electrons that the growth mechanism can be stable and that there is a perfect epitaxial relation from the low-off-axis substrate and the doped layer even when there is step-bunching.
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| 6. |
- Schimmel, S., et al.
(författare)
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Step-flow growth of fluorescent 4H-SiC layers on 4 degree off-axis substrates
- 2013
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Ingår i: Silicon Carbide and Related Materials 2012. - : Trans Tech Publications Inc.. - 9783037856246 ; , s. 185-188
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Konferensbidrag (refereegranskat)abstract
- Homoepitaxial layers of fluorescent 4H-SiC were grown on 4 degree off-axis substrates by sublimation epitaxy. Luminescence in the green spectral range was obtained by co-doping with nitrogen and boron utilizing donor-acceptor pair luminescence. This concept opens possibilities to explore green light emitting diodes using a new materials platform.
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| 7. |
- Taruscio, D, et al.
(författare)
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EUROPLAN: a project to support the development of national plans on rare diseases in Europe
- 2013
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Ingår i: Public health genomics. - : S. Karger AG. - 1662-8063 .- 1662-4246. ; 16:6, s. 278-287
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Tidskriftsartikel (refereegranskat)abstract
- <b><i>Background/Aims:</i></b> National Plans for Rare Diseases (RDs) are the common denominator of current public health policy concerns on RDs across the EU. With the aim of a better distribution of the available resources, they conjugate the European objective that aims at ensuring that patients with RDs have access to high-quality care - including diagnostics, treatment and rehabilitation - with the national priorities of selecting specific measures for adoption and implementation. <b><i>Methods:</i></b> The European Project for Rare Diseases National Plans Development (EUROPLAN, www.europlanproject.eu) is cofunded by the EU Commission (DG-SANCO) and is coordinated by the Italian National Center for Rare Diseases of the Istituto Superiore di Sanità (ISS). The EUROPLAN goal is to promote the implementation of National Plans or Strategies to tackle RDs and share relevant experiences within countries, linking national efforts, through a common strategy at a European level. In order to fulfill these objectives, EUROPLAN involved health authorities, clinicians, scientists, the European Organisation for Rare Diseases (EURORDIS), and many other patient groups as associated and collaborating partners from several European countries. <b><i>Results:</i></b> The project was launched in 2008 and foresaw 2 implementation phases: phase 1 (2008-2011) to build the consensus definition of operational tools (recommendations and indicators), and the ongoing phase 2 (2012-2015), mainly aimed at capacity building with the proactive involvement of multilevel stakeholders. EUROPLAN is facilitating and accelerating the implementation of National Plans in almost all EU and several non-EU Countries. <b><i>Conclusions:</i></b> EUROPLAN is a European and an international process more than a project, and it could be defined as a ‘litmus test' demonstrating how the collaboration between institutions and patients' associations can accelerate the process of awareness and development of policies and actions.
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