Space-qualified liquid-crystal variable retarders for wide-field-of-view coronagraphs

Uribe-Patarroyo, Néstor; Alvarez-Herrero, A.; Parejo, Pilar García; Vargas, Javier; Heredero, R. L.; Restrepo, René; Pillet, V. Martı́nez; Iniesta, J. C. del Toro; López, A.J.; Fineschi, Silvano; Capobianco, Gerardo; Georges, Marc; López, M. A. Hernández; Boer, Gerben; Manolis, Ilias

doi:10.1117/12.904919

Cited by 12 publications

(8 citation statements)

References 17 publications

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“…For the evaluation of the contribution of the IF filter an ellipsometer could be used 7,12 , for the others components of the polarimeter assembly and for the whole polarimeter, a prototype of a Mueller SpectroPolarimeter (MSP) is available and already used in the labs of the INAF-Turin Astrophysical Observatory 14,15,16,17 for this kind of calibrations. Some identified critical points related to the polarimeter that will be investigated are: the homogeneity of the retardance versus angle of incidence and versus temperature 18,19 .…”

Section: Instrumental Polarizationmentioning

confidence: 99%

Polarimetric calibrations and astronomical polarimetry in the V-band with Solar Orbiter/METIS instrument

Capobianco

Fineschi

Focardi³

et al. 2014

SPIE Proceedings

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METIS is one of the remote sensing instruments on board the ESA- Solar Orbiter mission, that will be launched in July 2017. The Visible Light Channel (VLC) of the instrument is composed by an achromatic LC-based polarimeter for the study of the linearly polarized solar K-corona in the 580-640 nm bandpass. The laboratory calibrations with spectropolarimetric techniques and the in-flight calibrations of this channel, using some well knows linearly polarized stars in the FoV of the instrument with a degree of linear polarization DOLP > 10% are here discussed. The selection of the stars and the use of other astronomical targets (i.e. planets, comets,…) and the opportunity of measurements of the degree of linear polarization in the visible bandpass of some astronomical objects (i.e. Earth, comets,…) are also objects of this paper

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Section: Instrumental Polarizationmentioning

confidence: 99%

Polarimetric calibrations and astronomical polarimetry in the V-band with Solar Orbiter/METIS instrument

Capobianco

Fineschi

Focardi³

et al. 2014

SPIE Proceedings

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“…36 LCVR's can be generally manufactured with larger apertures than other LC's (∼50 mm) and can be made more achromatic if two crystal layers are combined. 64,196 LCVR's were successfully employed in the ballon-borne IMAX instrument, and have been recently space qualified 197,198 and included in the PHI spectropolarimeter on board of the Solar Orbiter mission, see Table 2. Other recent LCVR developments in solar polarimetry include studying devices with different working principles, such as dual-frequency LC's (see below).…”

Section: Temporal Modulationmentioning

confidence: 99%

Instrumentation for solar spectropolarimetry: state of the art and prospects

Iglesias

Feller

2019

Opt. Eng.

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Given its unchallenged capabilities in terms of sensitivity and spatial resolution, the combination of imaging spectropolarimetry and numeric Stokes inversion represent the dominant technique currently used to remotely sense the physical properties of the solar atmosphere, and in particular, its important driving magnetic field. Solar magnetism manifests itself in a wide range of spatial, temporal and energetic scales. The ubiquitous but relatively small and weak fields of the so called quiet Sun are believed today to be crucial for answering many open questions in solar physics, some of which have substantial practical relevance due to the strong Sun-Earth connection. However, such fields are very challenging to detect because they require spectropolarimetric measurements with high spatial (subarcsec), spectral (< 100 m) and temporal (< 10 s) resolution along with high polarimetric sensitivity (< 0.1% of the intensity). In this review we collect and discuss both well-established and upcoming instrumental solutions developed during the last decades to push solar observations towards the above-mentioned parameter regime. This typically involves design trade-offs due to the high dimensionality of the data and signal-to-noise-ratio considerations, among others. We focus on the main three components that form a spectropolarimeter, namely, wavelength discriminators, the devices employed to encode the incoming polarization state into intensity images (polarization modulators), and the sensor technologies used to register them. We consider the instrumental solutions introduced to perform this kind of measurements at different optical wavelengths and from various observing locations, i.e., ground-based, from the stratosphere or near space.

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“…Moreover, technical solutions now exist to build wide-field and achromatic LCVRs. 71 Active liquid crystal elements have also been space-qualified, 72 and are finding their way into designs for satellite-based polarimeters.…”

Section: Liquid Crystal Componentsmentioning

confidence: 99%

An overview of polarimetric sensing techniques and technology with applications to different research fields

Snik¹,

Craven-Jones²,

Escuti³

et al. 2014

SPIE Proceedings

114

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We report the main conclusions from an interactive, multidisciplinary workshop on "Polarimetric Techniques and Technology", held on March 24-28 2014 at the Lorentz Center in Leiden, the Netherlands. The workshop brought together polarimetrists from different research fields. Participants had backgrounds ranging from academia to industrial R&D. Here we provide an overview of polarimetric instrumentation in the optical regime geared towards a wide range of applications: atmospheric remote sensing, target detection, astronomy, biomedical applications, etc. We identify common approaches and challenges. We list novel polarimetric techniques and polarization technologies that enable promising new solutions. We conclude with recommendations to the polarimetric community at large on joint efforts for exchanging expertise.

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Space-qualified liquid-crystal variable retarders for wide-field-of-view coronagraphs

Cited by 12 publications

References 17 publications

Polarimetric calibrations and astronomical polarimetry in the V-band with Solar Orbiter/METIS instrument

Polarimetric calibrations and astronomical polarimetry in the V-band with Solar Orbiter/METIS instrument

Instrumentation for solar spectropolarimetry: state of the art and prospects

An overview of polarimetric sensing techniques and technology with applications to different research fields

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