3 results on '"Aznárez, José Antonio"'
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2. Recubrimientos ópticos en el rango espectral entre 50 y 200 nm
- Author
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Fernández Perea, Mónica, Méndez, José Antonio, Larruquert, Juan Ignacio, and Aznárez, José Antonio
- Subjects
Reflectometry ,Extreme ultraviolet ,Thin films ,Optical coatings ,Far ultraviolet - Abstract
The development of efficient optical coatings in the spectral region between 50 and 200 nm (EUV-FUV) is an important challenge due to the great absortion and low reflectance that most of the materials present in this region. In addition, these coatings are an important element in the advance of many fields like astronomical abservations, plasma diagnosis and lithography. In this work we describe some of the optical coatings developed by the Research Group in Thin Film Coatings (GOLD), which operate in the EUV-FUV region of the spectrum. In GOLD we have an ultra high vacuum experimental system that permits the deposition and in situ measurement of the transmittance and reflectance of multilayers, as a function of the angle of incidence, and in the EUV-FUV spectral range. We prepare multilayers with up to six different materials, which can be deposited using three different techniques. In situ transmittance and reflectance measurements versus the angle of incidence permits the determination of the optical constants (n,k) of the materials, without being exposed to the atmosphere. Due to the great dependance between the optical properties of thin film layers in this spectral range, and the exposition to the atmosphere, our experimental system is a very adequate tool for the determination of those properties, and therefore for the design and fabrication of novel multilayers., El desarrollo de recubrimientos ópticos eficientes en la región espectral comprendida entre 50 y 200 nm (UVE-UVL) supone un reto debido a la gran absorción y baja reflectancia que presentan la mayoría de los materiales en este intervalo. Por otro lado estos recubrimientos son una pieza importante para el progreso de multitud de campos como las observaciones astronómicas, el diagnóstico de plasmas y la litografía. En este trabajo se describen algunos de los recubrimientos ópticos desarrollados hasta el momento por el Grupo de investigación en Óptica de Láminas Delgadas (GOLD), que operan en la región UVE-UVL del espectro. En GOLD disponemos de un equipo experimental de ultra-alto vacío que permite la deposición y medida in situ de la transmitancia y la reflectancia de multicapas en función del ángulo de incidencia y en el rango espectral UVL-UVE. Las multicapas están formadas por hasta seis materiales distintos, que pueden ser depositados mediante tres técnicas de preparación diferentes. Las medidas de transmitancia y reflectancia en función del ángulo de incidencia realizadas in situ permiten la determinación de las constantes ópticas (n, k) de los materiales sin que hayan sido expuestos a la atmósfera. Dada la gran dependencia existente entre las propiedades ópticas de las láminas delgadas y la exposición atmosférica en este rango espectral, nuestro equipo experimental constituye una herramienta muy adecuada para su determinación, y por lo tanto para el diseño y preparación de multicapas innovadoras., Mónica Fernández Perea agradece al Consejo Superior de Investigaciones Científicas la financiación a través del programa de becas predoctorales I3P.
- Published
- 2006
3. Novel narrow filters for imaging in the 50–150 nm VUV range.
- Author
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Fernández-Perea, Mónica, Vidal-Dasilva, Manuela, Larruquert, Juan Ignacio, Méndez, José Antonio, and Aznárez, José Antonio
- Subjects
ULTRAVIOLET astronomy ,SOLAR research ,ATMOSPHERIC physics ,WAVELENGTHS ,SURFACES (Technology) ,OPTICAL coatings - Abstract
GOLD (Grupo de Óptica de Láminas Delgadas) is devoted to the development of novel coatings with challenging performance in the far and the extreme ultraviolet (FUV-EUV, 50–200 nm). One of the main goals of this research is to provide the communities of astronomy, solar physics and atmospheric physics with coatings with high reflectance or transmittance at a target wavelength or band, and high rejection of the out-of-band at this complicated spectral range. Above the transparency cutoff of MgF
2 (115 nm), transmittance filters based on Al/MgF2 multilayers have been developed peaked at wavelengths as short as 124 nm, with a peak transmittance of 27% and a FWHM of 12 nm for a non-aged coating. Below 115 nm, a research on reflectance filters has recently started with very promising results on filters peaked at the 83.4 nm OII spectral line. Fresh filters with 27% peak reflectance at normal incidence and a FWHM of 14 nm have been obtained. Furthermore, the peak reflectance wavelength of these filters can be tuned by rotation. A filter peaked at 83 nm at normal incidence will shift to ∼73 nm at 30 deg from the normal and to ∼58 nm at 45 deg. These novel reflective filters based on Al, Yb and SiO must still demonstrate stability over time. [ABSTRACT FROM AUTHOR]- Published
- 2008
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