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MEGARA anti-reflective coatings: theoretical and observed throughput estimations
Author(s): R. Ortiz; E. Carrasco; G. Páez; O. Pompa; E. Sánchez-Blanco; A. Gil de Paz; J. Gallego; J. Iglesias-Páramo
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Paper Abstract

MEGARA is the new integral field unit (IFU) and multi-object (MOS) spectrograph successfully commissioned at Gran Telescopio Canarias, in August 2017. MEGARA provides spectral resolutions R (fwhm) ~ 6000, 12000 and 20000, via volume phase holographic gratings, at very high efficiency in both IFU and MOS modes. In the case of MEGARA main optics and pupil elements optics, the surfaces in contact with air have an anti-reflective (AR) coatings to minimize the Fresnel losses at the interface glass-air. In this work we present the designs and calculation of the total throughput of the optical system based in the transmission measurements of the AR coated witness samples. The results reflect the benefits of having implemented customized AR coatings for the mean angle of incidence on each surface as the measured throughput was better than the requirements. We analyze the effects of the pupil elements AR coatings for each spectral configuration.

Paper Details

Date Published: 10 July 2018
PDF: 12 pages
Proc. SPIE 10706, Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation III, 107065H (10 July 2018); doi: 10.1117/12.2313976
Show Author Affiliations
R. Ortiz, Instituto Nacional de Astrofísica, Óptica y Electrónica (Mexico)
E. Carrasco, Instituto Nacional de Astrofísica, Óptica y Electrónica (Mexico)
G. Páez, Ctr. de Investigaciones en Óptica, A.C. (Mexico)
O. Pompa, Ctr. de Investigaciones en Óptica, A.C. (Mexico)
E. Sánchez-Blanco, FRACTAL S.L.N.E. (Spain)
A. Gil de Paz, Univ. Complutense de Madrid (Spain)
J. Gallego, Univ. Complutense de Madrid (Spain)
J. Iglesias-Páramo, Instituto de Astrofísica de Andalucía (Spain)


Published in SPIE Proceedings Vol. 10706:
Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation III
Ramón Navarro; Roland Geyl, Editor(s)

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