English
Related papers

Related papers: The IRCAL Polarimeter: Design, Calibration, and Da…

200 papers

Taking advantage of the advances in array detector technology, an imaging polarimeter (IMPOL) has been constructed for measuring linear polarization in the wavelength band from 400-800 nm. It makes use of a Wollaston prism as the analyser…

Astrophysics · Physics 2009-09-15 A. N. Ramaprakash , Ranjan Gupta , A. K. Sen , S. N. Tandon

Multi-wavelength imaging polarimetry at far-infrared wavelengths has proven to be an excellent tool for studying the physical properties of dust, molecular clouds, and magnetic fields in the interstellar medium. Although these wavelengths…

We describe a new instrument that forms the core of a long-term high contrast imaging program at the 200-inch Hale Telescope at Palomar Observatory. The primary scientific thrust is to obtain images and low-resolution spectroscopy of brown…

We have built and tested a compact, low-cost, but very-high-performance astronomical polarimeter based on a continuously rotating half-wave plate and a high-speed imaging detector. The polarimeter is suitable for small telescopes up to ~1 m…

Instrumentation and Methods for Astrophysics · Physics 2023-02-08 Jeremy Bailey , Daniel V. Cotton , Ain De Horta , Lucyna Kedziora-Chudczer , Om Shastri

As a Near-IR instrument to PRL's upcoming 2.5 m telescope, NISP is designed indigeniously at PRL to serve as a multifaceted instrument. Optical, Mechanical and Electronics subsystems are being designed and developed in-house at PRL. It will…

WIRC+Pol is a newly commissioned low-resolution (R~100), near-infrared (J and H band) spectropolarimetry mode of the Wide-field InfraRed Camera (WIRC) on the 200-inch Hale Telescope at Palomar Observatory. The instrument utilizes a novel…

Imaging polarimetry is a powerful tool for detecting and characterizing exoplanets and circumstellar environments. Polarimetry allows a separation of the light coming from an unpolarized source such as a star and the polarized source such…

Instrumentation and Methods for Astrophysics · Physics 2015-05-28 H. Canovas , M. Rodenhuis , S. V. Jeffers , M. Min , C. U. Keller

In the last decade, imaging polarimeters based on micropolarizer arrays have been developed for use in terrestrial remote sensing and metrology applications. Micropolarizer-based sensors are dramatically smaller and more mechanically robust…

Instrumentation and Methods for Astrophysics · Physics 2018-04-26 Dmitry Vorobiev , Zoran Ninkov , Neal Brock

We designed and built a new astronomical photo-polarimeter that can measure linear polarization simultaneously in three spectral bands. It has a Calcite beamdisplacement prism as the analyzer. The ordinary and extra-ordinary emerging beams…

Instrumentation and Methods for Astrophysics · Physics 2015-05-19 G. Srinivasulu , A. V. Raveendran , S. Muneer , M. V. Mekkaden , N. Jayavel , M. R. Somashekar , K. Sagayanathan , S. Ramamoorthy , M. J. Rosario , K. Jayakumar

This work presents a comprehensive examination of the use of information theory for understanding Polarimetric Synthetic Aperture Radar (PolSAR) images by means of contrast measures that can be used as test statistics. Due to the phenomenon…

Methodology · Statistics 2014-02-11 A. C. Frery , A. D. C. Nascimento , R. J. Cintra

A new astronomical photo-polarimeter that can measure linear polarization of point sources simultaneously in three spectral bands was designed and built in Indian Institute of Astrophysics. The polarimeter has a Calcite beam-displacement…

Instrumentation and Methods for Astrophysics · Physics 2015-06-30 A. V. Raveendran , G. Srinivasulu , S. Muneer , M. V. Mekkaden , N. Jayavel , M. R. Somashekar , K. Sagayanathan , S. Ramamoorthy , M. J. Rosario , K. Jayakumar

In this paper, we introduce an iterative speckle filtering method for polarimetric SAR (PolSAR) images based on the bilateral filter. To locally adapt to the spatial structure of images, this filter relies on pixel similarities in both…

Computer Vision and Pattern Recognition · Computer Science 2013-11-04 Olivier D'Hondt , Stéphane Guillaso , Olaf Hellwich

WIRC+Pol is a near-infrared low-resolution spectropolarimeter on the 200-inch Telescope at Palomar Observatory. The instrument utilizes a polarization grating to perform polarimetric beam splitting and spectral dispersion simultaneously. It…

We describe and report first results from PALM-3000, the second-generation astronomical adaptive optics facility for the 5.1-m Hale telescope at Palomar Observatory. PALM-3000 has been engineered for high-contrast imaging and emission…

This paper presents a technique for reducing speckle in Polarimetric Synthetic Aperture Radar (PolSAR) imagery using Nonlocal Means and a statistical test based on stochastic divergences. The main objective is to select homogeneous pixels…

Information Theory · Computer Science 2013-04-18 Leonardo Torres , Sidnei J. S. Sant'Anna , Corina C. Freitas , Alejandro C. Frery

Interferometric scattering microscopy was widely applied in nanoscopic detection and tracking due to its high sensitivity and label-free manner. The sensitivity is limited by contrast. Oblique illumination provided high contrast with lower…

Optics · Physics 2025-11-11 Xiang Zhang , Wenfu Lin , Yatao Yang , Yifan Wang

Polarimetric interferometry is a method allowing the study of the distribution of polarized flux at diffraction-limited resolution. Its basic observable is the ratio $\mathcal{R}$ of the visibilities of the object in two orthogonal…

Instrumentation and Methods for Astrophysics · Physics 2019-02-27 Boris Safonov , Pavel Lysenko , Maria Goliguzova , Dmitry Cheryasov

Imaging both the polarization and the wavefront of a light beam is a complex task that typically demands several intensity acquisitions. Furthermore, sequential acquisition solutions are incompatible with the monitoring of ultra-fast…

Optics · Physics 2024-07-30 Baptiste Blochet , Grégoire Lelu , Miguel A. Alonso , Marc Guillon

Well over 700 exoplanets have been detected to date. Only a handful of these have been observed directly. Direct observation is extremely challenging due to the small separation and very large contrast involved. Imaging polarimetry offers a…

Instrumentation and Methods for Astrophysics · Physics 2015-06-12 M. Rodenhuis , H. Canovas , S. V. Jeffers , M. de Juan Ovelar , L. Homs , M. Min , C. U. Keller

Polarization plays an important role in various time-domain astrophysics to understand the magnetic fields, geometry, and environments of spatially unresolved variable sources. In this paper we present the results of laboratory and on-sky…

Instrumentation and Methods for Astrophysics · Physics 2020-04-29 Manisha Shrestha , Iain A. Steele , Andrez S. Piascik , Helen Jermak , Robert J. Smith , Chris M. Copperwheat
‹ Prev 1 2 3 10 Next ›