Band-limited masks for TPF coronagraph

Balasubramanian, Kunjithapatham; Sidick, Erkin; Wilson, Daniel W.; Hoppe, Daniel; Shaklan, Stuart; Trauger, John T.

doi:10.1016/j.crhy.2007.03.001

Cited by 4 publications

(2 citation statements)

References 10 publications

(23 reference statements)

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“…In addition, all of the broadband contrast numbers presented here are dominated by the variations of occulter phase with wavelength inherent in HEBS glass profiles. Occulting profiles created by variable-thickness metallic coatings, for example, have very different phase behavior than HEBS, and in many cases achieve much better broadband contrasts [10][11][12][13].…”

Section: Resultsmentioning

confidence: 98%

Optimizing the broadband performance of TPF's high-contrast imaging testbed through modeling and simulations

2007

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We have carried out some investigation to optimize the broadband performance of the high-contrast imaging testbed (HCIT) at JPL through optical modeling and simulations. The analytical tool is an optical simulation algorithm developed by combining the HCIT's optical model with a speckle-nulling algorithm that operates directly on coronagraphic images, an algorithm very similar to the one that has been used on the HCIT. We have experimented in our simulations with different designs for the occulting mask and the Lyot Stop, and also tried several different specklenulling approaches. Some results predicted by our simulations agree well with the results measured on the HCIT. In this paper we describe the details of our simulations and present our results.

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Section: Resultsmentioning

confidence: 98%

Optimizing the broadband performance of TPF's high-contrast imaging testbed through modeling and simulations

2007

Self Cite

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“…Coronagraph masks can be manufactured by a variety of techniques, including e-beam exposure 2 of high-energy beam sensitive (HEBS) glass (manufactured by Canyon Materials 3 ), binary patterns written in metal films on glass with lithography techniques 4 , and vapor deposition of thickness-profiled metal films on glass substrates. The best laboratory contrast results to date, 5×10 -10 in narrowband light, have been achieved in using masks fabricated with HEBS glass 5,6 .…”

Section: Introductionmentioning

confidence: 99%

Hybrid Lyot coronagraph masks and wavefront control for improved spectral bandwidth and throughput

Moody

Trauger

2007

SPIE Proceedings

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Coronagraph focal-plane occulting masks have generally been described as attenuation profiles free of any phase shift. However, phase shifts are expected and observed in physical occulting masks, and they can impose significant limitations on coronagraph contrast at the billion-to-one level in spectrally broad light, as required for the direct imaging of planetary systems orbiting the nearby stars. Here we explore design options for a physically realizable occulting mask composed of a metallic and a dielectric thin film, each profiled in thickness and superimposed on a glass substrate. We show that such hybrid masks, together with a deformable mirror for control of wavefront phase, offer contrast performance better than 10 -9 over spectral bandwidths up to 30% with Lyot coronagraph throughput efficiencies of 66% or more.

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Requirements on optical density and phase dispersion of imperfect band-limited occulting masks in a broadband coronagraph

Sidick

2007

Appl. Opt.

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We investigate the effects of the parasitic phase of imperfect band-limited occulting masks on the broadband contrast performance of a high-contrast imaging system through modeling and simulations. We also examine the effects of the phase and the optical-density dispersions of occulting masks whose parasitic phase has been compensated at the center wavelength but is nonzero at other wavelengths. Two types of occulting masks are considered: gray-scale masks such as those made on a high-energy beam-sensitive glass, and recently proposed spatially profiled metal masks, both having 1D Sinc2(linear-Sinc2) amplitude transmission coefficient (Sinc4 intensity transmittance) profiles. We determine the conditions for obtaining 1x10(-9) and 1x10(-10) contrast values with a light centered at a 785 nm wavelength and having a 10% bandwidth in a coronagraphic telescope having ideal optical surfaces but imperfect band-limited image-plane occulting masks.

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Band-limited masks for TPF coronagraph

Cited by 4 publications

References 10 publications

Optimizing the broadband performance of TPF's high-contrast imaging testbed through modeling and simulations

Optimizing the broadband performance of TPF's high-contrast imaging testbed through modeling and simulations

Hybrid Lyot coronagraph masks and wavefront control for improved spectral bandwidth and throughput

Requirements on optical density and phase dispersion of imperfect band-limited occulting masks in a broadband coronagraph

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