Examinando por Autor "Uribe Patarroyo, N."

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Imaging polarimeters based on liquid crystal variable retarders: an emergent technology for space instrumentation
(SPIE Optical Engineering Applications, 2011-09-09) Álvarez Herrero, A.; Uribe Patarroyo, N.; García Parejo, P.; Vargas, J.; López Heredero, R.; Restrepo, R.; Martínez Pillet, V.; Del Toro Iniesta, J. C.; López, A.; Fineschi, S.; Capobianco, G.; Georges, M.; López, M.; Boer, G.; Manolis, I.; López Heredero, R. [0000-0002-2197-8388]; Vargas, J. [0000-0001-7519-6106]; García Parejo, P. [0000-0003-1556-9411]; López Jiménez, A. [0000-0002-6297-0681]; Del Toro Iniesta, J. A. [0000-0002-3387-026X]; Álvarez Herrero, A. [0000-0001-9228-3412]; Capobianco, G. [0000-0003-0520-2528]; Restrepo Gómez, R. [0000-0002-3874-3032]; Georges, M. [0000-0002-0460-3912]; Martínez Pillet, V. [0000-0001-7764-6895]
The use of Liquid Crystal Variable Retarders (LCVRs) as polarization modulators are envisaged as a promising novel technique for space instrumentation due to the inherent advantage of eliminating the need for conventional rotary polarizing optics hence the need of mechanisms. LCVRs is a mature technology for ground applications; they are wellknow, already used in polarimeters, and during the last ten years have undergone an important development, driven by the fast expansion of commercial Liquid Crystal Displays. In this work a brief review of the state of the art of imaging polarimeters based on LCVRs is presented. All of them are ground instruments, except the solar magnetograph IMaX which flew in 2009 onboard of a stratospheric balloon as part of the SUNRISE mission payload, since we have no knowledge about other spaceborne polarimeters using liquid crystal up to now. Also the main results of the activity, which was recently completed, with the objective to validate the LCVRs technology for the Solar Orbiter space mission are described. In the aforementioned mission, LCVRs will be utilized in the polarisation modulation package of the instruments SO/PHI (Polarimetric and Helioseismic Imager for Solar Orbiter) and METIS/COR (Multi Element Telescope for Imaging and Spectroscopy, Coronagraph).
Restringido
IMaX: a polarimeter based on Liquid Crystal Variable Retarders for an aerospace mission
(Wiley Online Library, 2008-05-08) Uribe Patarroyo, N.; Álvarez Herrero, A.; López Heredero, R.; Del Toro Iniesta, J. C.; López Jiménez, A. C.; Domingo, V.; Gasent, J. L.; Jochum, L.; Martínez Pillet, V.; Del Toro Iniesta, J. C. [0000-0002-3387-026X]; López Jiménez, A. [0000-0002-6297-0681]; López Heredero, R. [0000-0002-2197-8388]; Álvarez Herrero, A. [0000-0001-9228-3412]; Gasenta Blesa, J. L. [0000-0002-1225-4177]; Martínez Pillet, V. [0000-0001-7764-6895]
IMaX is the Imaging Magnetograph eXperiment, an instrument part of the payload of SUNRISE, a stratospheric balloon mission in Antarctica. It is also the precursor of the Visible Imaging Magnetograph of the future ESA Solar Orbiter mission. It is essentially a diffraction-limited imager that carries out spectropolarimetric measurements of high resolution (bandwidth of < 100 mÅ at 525.02 nm), and relates the polarimetric properties of the incoming light through a telescope with magnetic fields in the Sun, via the Zeeman effect. At the core of the instrument there are the polarization modulation components, two Liquid Crystal Variable Retarders (LCVRs). A demodulation efficiency is defined and used as the figure of merit, and it serves to find the theoretical optimum states for the LCVRs as well as to judge the quality of the pre-flight calibration of the system. This calibration and the method used to optimize the actual efficiency is explained. Also, the space qualification of the LCVRs is presented, where ellipsometry played a major role in studying the effects of radiation, vacuum and temperature in the operation of the LCVRs. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Restringido
Liquid-crystal variable retarders for aerospace polarimetry applications
(OSA (The Optical Society) Publishing, 2007-01-25) López Heredero, R.; Uribe Patarroyo, N.; Belenguer, T.; Ramos, G.; Sánchez, A.; Reina, M.; Martínez Pillet, V.; Álvarez Herrero, A.; Álvarez Herrero, A. [0000-0001-9228-3412]; López Heredero, R. [0000-0002-2197-8388]; Martínez Pillet, V. [0000-0001-7764-6895]
We present the optical effects of different tests that simulate the aerospace environment on the liquid-crystal variable retarders (LCVRs) used in the Imaging Magnetograph eXperiment postfocal instrument of the SUNRISE payload within the NASA Long Duration Balloon program. Analysis of the influence of vacuum, temperature, vibration, and gamma and ultraviolet radiation is performed by measuring the effects of these tests on the optical retardance, the response time, the wavefront distortion, and the transmittance, including some in situ measurements. Outgassing measurements of the different parts of the LCVRs are also shown. From the results obtained it can be concluded that these optical devices are suitable and seem to be excellent candidates for aerospace platforms.
Restringido
Space-qualified liquid-crystal variable retarders for wide-field-of-view coronagraphs
(SPIE Optical Engineering Applications, 2011-10-06) Uribe Patarroyo, N.; Álvarez Herrero, A.; García Parejo, P.; Vargas, J.; Heredero, R. L.; Restrepo, R.; Martínez Pillet, V.; Del Toro Iniesta, J. C.; López, A.; Fineschi, S.; Capobianco, G.; Georges, M.; López, M.; Boer, G.; Manolis, I.; Álvarez Herrero, A. [0000-0001-9228-3412]; Del Toro Iniesta, J. C. [0000-0002-3387-026X]; López Heredero, R. [0000-0002-2197-8388]; Vargas, J. [0000-0001-7519-6106]; López Jiménez, A. [0000-0002-6297-0681]; García Parejo, P. [0000-0003-1556-9411]; Capobianco, G. [0000-0003-0520-2528]; Georges, M. [0000-0002-0460-3912]; Restrepo Gómez, R. [0000-0002-3874-3032]; Martínez Pillet, V. [0000-0001-7764-6895]
Liquid-crystal variable retarders (LCVRs) are an emergent technology for space-based polarimeters, following its success as polarization modulators in ground-based polarimeters and ellipsometers. Wide-field double nematic LCVRs address the high angular sensitivity of nematic LCVRs at some voltage regimes. We present a work in which wide-field LCVRs were designed and built, which are suitable for wide-field-of-view instruments such as polarimetric coronagraphs. A detailed model of their angular acceptance was made, and we validated this technology for space environmental conditions, including a campaign studying the effects of gamma, proton irradiation, vibration and shock, thermo-vacuum and ultraviolet radiation.
Acceso Abierto
The Imaging Magnetograph eXperiment (IMaX) for the Sunrise Balloon-Borne Solar Observatory
(Springer Link, 2011-01-17) Martínez Pillet, V.; Del Toro Iniesta, J. C.; Álvarez Herrero, A.; Domingo, V.; Bonet, J. A.; González Fernández, C.; López Jiménez, A.; Pastor, C.; Gasent Blesa, J. L.; Mellado, P.; Piqueras, J.; Aparicio, B.; Balaguer, M.; Ballesteros, E.; Belenguer, T.; Bellot Rubio, L. R.; Berkefeld, T.; Collados, M.; Deutsch, W.; Feller, A.; Girela, F.; Grauf, B.; Heredero, R. L.; Herranz, M.; Jerónimo, J. M.; Laguna, H.; Meller, R.; Menéndez, M.; Morales, R.; Orozco Suárez, D.; Ramos, G.; Reina, M.; Ramos, J. L.; Rodríguez, P.; Sánchez, A.; Uribe Patarroyo, N.; Barthol, P.; Gandorfer, A.; Knoelker, M.; Schmidt, W.; Solanki, S. K.; Vargas Domínguez, S.; Ministerio de Ciencia e Innovación (MICINN); Deutsches Zentrum für Luft- und Raumfahrt (DLR); National Aeronautics and Space Administration (NASA); López Heredero, R. [0000-0002-2197-8388]; López Jiménez, A. [0000-0002-6297-0681]; Balaguer, M. [0000-0003-4738-7727]; Del Toro Iniesta, J. C. [0000-0002-3387-026X]; Reina Aranda, M. [0000-0003-0248-2771]; Álvarez Herrero, A. [0000-0001-9228-3412]; Herranz de la Revilla, M. L. [0000-0003-4343-6632]; Morales Muñoz, R. [0000-0003-1661-0594]; Pastor, C. [0000-0001-9631-9558]; Gasent Blesa, J. L. [0000-0002-1225-4177]; Collados, M. [0000-0002-6210-9648]; Jerónimo, J. M. [0000-0002-4944-5823]; Bellot Rubio, L. R. [0000-0001-8669-8857]; Martínez Pillet, V. [0000-0001-7764-6895]
The Imaging Magnetograph eXperiment (IMaX) is a spectropolarimeter built by four institutions in Spain that flew on board the Sunrise balloon-borne solar observatory in June 2009 for almost six days over the Arctic Circle. As a polarimeter, IMaX uses fast polarization modulation (based on the use of two liquid crystal retarders), real-time image accumulation, and dual-beam polarimetry to reach polarization sensitivities of 0.1%. As a spectrograph, the instrument uses a LiNbO3 etalon in double pass and a narrow band pre-filter to achieve a spectral resolution of 85 mÅ. IMaX uses the high-Zeeman-sensitive line of Fe I at 5250.2 Å and observes all four Stokes parameters at various points inside the spectral line. This allows vector magnetograms, Dopplergrams, and intensity frames to be produced that, after reconstruction, reach spatial resolutions in the 0.15 – 0.18 arcsec range over a 50×50 arcsec field of view. Time cadences vary between 10 and 33 s, although the shortest one only includes longitudinal polarimetry. The spectral line is sampled in various ways depending on the applied observing mode, from just two points inside the line to 11 of them. All observing modes include one extra wavelength point in the nearby continuum. Gauss equivalent sensitivities are 4 G for longitudinal fields and 80 G for transverse fields per wavelength sample. The line-of-sight velocities are estimated with statistical errors of the order of 5 – 40 m s−1. The design, calibration, and integration phases of the instrument, together with the implemented data reduction scheme, are described in some detail.