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Due to the low flux of exoEarths, long exposure times are required to spectrally characterize them. During these long exposures, the contrast in the dark hole will degrade as the the optical system drifts from its initial DH state. To…

Instrumentation and Methods for Astrophysics · Physics 2023-10-02 Phillip K. Poon , Axel Potier , Garreth Ruane , Alex B. Walter , A J Eldorado Riggs , Matthew Noyes , Camilo Mejia Prada , Kyohoon Ahn , Olivier Guyon

Ferroelectric liquid crystals (FLCs) couple the direction of their spontaneous electric polarization to the direction of tilt of their optic axis. Consequently, reversal of the electric polarization by an electric field gives rise to an…

Context. Phase-mask coronagraphy is advantageous in terms of inner working angle and discovery space. It is however still plagued by drawbacks such as sensitivity to tip-tilt errors and chromatism. A nulling stellar coronagraph based on the…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 P. Bourget , N. Schuhler , D. Mawet , P. Haguenauer

The characterization of exoplanet atmospheres using direct imaging spectroscopy requires high-contrast over a wide wavelength range. We study a recently proposed focal plane wavefront estimation algorithm that exclusively uses broadband…

Instrumentation and Methods for Astrophysics · Physics 2021-08-19 Susan F. Redmond , Laurent Pueyo , Leonid Pogorelyuk , James Noss , Scott D. Will , Iva Laginja , N. Jeremy Kasdin , Marshall D. Perrin , Remi Soummer

The Roman coronagraph instrument will demonstrate high-contrast imaging technology, enabling the imaging of faint debris disks, the discovery of inner dust belts, and planets. Polarization studies of debris disks provide information on dust…

Instrumentation and Methods for Astrophysics · Physics 2022-09-07 Ramya Manjunath Anche , Ewan S. Douglas , Kian Milani , Jaren Ashcraft , John H Debes

To detect Earth-like planets in the visible with a coronagraphic telescope, two major noise sources have to be overcome: the photon noise of the diffracted star light, and the speckle noise due to the star light scattered by instrumental…

Specific high contrast imaging instruments are mandatory to characterize circumstellar disks and exoplanets around nearby stars. Coronagraphs are commonly used in these facilities to reject the diffracted light of an observed star and…

Instrumentation and Methods for Astrophysics · Physics 2016-08-10 J. R. Delorme , M. N'Diaye , R. Galicher , K. Dohlen , P. Baudoz , A. Caillat , G. Rousset , R. Soummer , O. Dupuis

We review methods to measure magnetic fields within the corona using the polarized light in magnetic-dipole (M1) lines. We are particularly interested in both the global magnetic-field evolution over a solar cycle, and the local storage of…

Solar and Stellar Astrophysics · Physics 2015-06-15 Philip G. Judge , Shadia Habbal , Enrico Landi

We present a method for measuring CMB polarization power spectra given incomplete sky coverage and test it with simulated examples such as Boomerang 2001 and MAP. By augmenting the quadratic estimator method with an additional step, we find…

Astrophysics · Physics 2009-10-07 Max Tegmark , Angelica de Oliveira-Costa

Ferroelectric materials possess spontaneous polarization that can be used for multiple applications. Owing to a long term development for reducing the sizes of devices, the preparation of ferroelectric materials and devices are entering…

The vector vortex coronagraph (VVC) performance in the laboratory and in ground-based observatories has earned it a spot on the NASA mission concepts HabEx and LUVOIR. The VVC induces a phase ramp through the manipulation of the…

Instrumentation and Methods for Astrophysics · Physics 2021-08-18 Jorge Llop-Sayson , Cole Kappel , Nemanja Jovanovic , Dimitri Mawet

Following the tracks of Malbet, Yu, & Shao (1995} on dark hole algorithms, we present analytical methods to measure and correct the speckle noise behind an ideal coronagraph. We show that, in a low aberration regime, wavefront sensing can…

Astrophysics · Physics 2009-11-11 Pascal Borde , Wesley Traub

Interstellar linear polarization occurs when starlight passes through elongated dust grains aligned by interstellar magnetic fields. The observed polarization can come from different dust structures along the line of sight (LOS). By…

Electrode polarization error is the biggest problem when measuring the low frequency dielectric properties of electrolytes or suspensions of particles, including cells, in electrolytes. We present a simple and robust method to remove the…

Soft Condensed Matter · Physics 2008-05-13 Camelia Prodan , Corina Bot

We have performed a novel comparison between electron-beam polarimeters based on M{\o}ller and Compton scattering. A sequence of electron-beam polarization measurements were performed at low beam currents ($<$ 5 $\mu$A) during the $Q_{\rm…

A large number of coronagraphs have been proposed to overcome the ratio that exists between the star and its planet. The planet finder of the Extremely Large Telescope, which is called EPICS, will certainly need a more efficient coronagraph…

Astrophysics · Physics 2009-11-13 P. Baudoz , R. Galicher , J. Baudrand , A. Boccaletti

Directly imaging Earth-sized exoplanets with a visible-light coronagraph instrument on a space telescope will require a system that can achieve $\sim10^{-10}$ raw contrast and maintain it for the duration of observations (on the order of…

The Habitable Worlds Observatory (HWO) is a flagship mission concept proposing to characterize earth-like exoplanets at high contrast with a coronagraph instrument. The most in-depth, validated contrast error budgets made to date have been…

Instrumentation and Methods for Astrophysics · Physics 2025-08-28 Emory L. Jenkins , A J Eldorado Riggs , Ewan S. Douglas , Ramya M. Anche , Dylan M. McKeithen , Stuart B. Shaklan

We describe a real-space approach to the calculation of the properties of an insulating crystal in an applied electric field, based on the iterative determination of the Wannier functions (WF's) of the occupied bands. It has been recently…

Condensed Matter · Physics 2009-10-22 R. W. Nunes , David Vanderbilt

The search for life via characterization of earth-like planets in the habitable zone is one of the key scientific objectives in Astronomy. We describe a new phase-occulting (PO) interferometric nulling coronagraphy (NC) approach. The PO-NC…

Instrumentation and Methods for Astrophysics · Physics 2015-04-23 Richard G. Lyon , Brian A. Hicks , Mark Clampin , Peter Petrone