2024-03-28T10:51:56Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/1540822022-06-10T10:16:46Zcom_10261_93com_10261_4col_10261_346
http://hdl.handle.net/10261/154082
10.1117/12.2232616
333481
Advances in far-ultraviolet reflective and transmissive coatings for space applications
The International Society for Optics and Photonics
2016
artículo
Rodríguez de Marcos, Luís
Aznárez, José Antonio
Méndez, José Antonio
Larruquert, Juan Ignacio
Vidal Dasilva, Manuela
Malvezzi, A. Marco
Giglia, Angelo
Capobianco, Gerardo
Fineschi,Silvano
Nannarone, S.
2016-07-22
10 pags., 8 figs.
Conference Volume 9912. Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation II, Edinburgh, United Kingdom, June 26, 2016
Conferencia programada dentro de Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation, part of SPIE Astronomical Telescopes + Instrumentation.
Exploitation of far ultraviolet (FUV, 100-200 nm) observations extends to most areas of modern astronomy, from detailed observations of Solar System objects, the interstellar medium, exoplanets, stars and galaxies, to studies of crucial cosmological relevance. Despite several developments in recent decades, yet many observations are not possible due to technical limitations, of which one of the most important is the lack of optical coatings with high throughput. Development and optimization of such efficient FUV coatings have been identified in several roadmap reports as a key goal for future missions. The success of this development will ultimately improve the performance of nowadays feasible optical instruments and will enable new scientific imaging capabilities.
GOLD’s research is devoted to developing novel coatings with enhanced performance for space optics. Several deposition systems are available for the deposition of multilayer coatings. A deposition system was developed to deposit FUV coatings to satisfy space requirements. It consists of a 75-cm-diameter deposition chamber pumped with a cryo-pump and placed in an ISO-6 clean room. This chamber is available for deposition by evaporation of top-requirement coatings such as Al/ MgF2 mirrors or (Al/MgF2)n multilayer coatings for transmittance filters. A plan to add an Ion-Beam-Sputtering system in this chamber is under way.
In this and other chambers at GOLD the following FUV coatings can be prepared:
Transmittance filters based on (Al/MgF2)n multilayer coatings. These filters can be designed to have a peak at the FUV spectral line or band of interest and a high peak-to-visible transmittance ratio. Filters can be designed with a peak transmittance at a wavelength as short as 120 nm and with a transmittance in the visible smaller than 10-5.
Narrowband reflective coatings peaked close to H Lyman β (102.6 nm) with a reflectance at H Lyman α (121.6 nm) two orders of magnitude below the one at 102.6 nm. Other potential spectral lines at which these coatings could be peaked are the OVI doublet (103.2, 103.8 nm).
Narrowband reflective mirrors based on (MgF2/LaF3)n multilayers peaked at a wavelength as short as 120 nm. Target wavelengths include lines of high interest for space observations, such as H Lyman α (121.6 nm), OI (130.4 and 135.6 nm), CIV (154.8, 155.1 nm), among others.
Coating-based linear polarizers tuned at H Lyman α (121.6 nm) both based on reflectance or on transmittance. Reflective polarizers present a high efficiency. Transmissive polarizers have a more modest peak performance compared to reflective polarizers; however, they involve spectral filtering properties to reject the long FUV and even more the near UV to the IR, which turn them competitive compared to reflective polarizers.
In this communication we present a summary of our research on the above FUV coatings developed at GOLD. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).
Ministerio de Economía y Competitividad (España)
SPIE Digital Library 9912