A Method to Image Extrasolar Planets with Polarized Light

Baba, Naoshi; Murakami, Naoshi

doi:10.1086/380422

Cited by 60 publications

(30 citation statements)

References 20 publications

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“…Several ways are used to measure that reference: spectral characteristics (Racine et al 1999;Marois et al 2000Marois et al , 2004, polarization states (Baba & Murakami 2003;Stam et al 2004), differential rotation in image (Schneider et al 1998b;Marois et al 2006), or incoherence between stellar and companion lights (Guyon 2004). The self-coherent camera with which we work uses the last property Galicher & Baudoz 2007).…”

Section: Introductionmentioning

confidence: 99%

Self-coherent camera as a focal plane wavefront sensor: simulations

Galicher

Baudoz

Rousset

et al. 2009

A&A

111

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Context. Direct detection of exoplanets requires high dynamic range imaging. Coronagraphs could be the solution, but their performance in space is limited by wavefront errors (manufacturing errors on optics, temperature variations, etc.), which create quasi-static stellar speckles in the final image. Aims. Several solutions have been suggested for tackling this speckle noise. Differential imaging techniques substract a reference image to the coronagraphic residue in a post-processing imaging. Other techniques attempt to actively correct wavefront errors using a deformable mirror. In that case, wavefront aberrations have to be measured in the science image to extremely high accuracy. Methods. We propose the self-coherent camera sequentially used as a focal-plane wavefront sensor for active correction and differential imaging. For both uses, stellar speckles are spatially encoded in the science image so that differential aberrations are strongly minimized. The encoding is based on the principle of light incoherence between the hosting star and its environment. Results. In this paper, we first discuss one intrinsic limitation of deformable mirrors. Then, several parameters of the self-coherent camera are studied in detail. We also propose an easy and robust design to associate the self-coherent camera with a coronagraph that uses a Lyot stop. Finally, we discuss the case of the association with a four-quadrant phase mask and numerically demonstrate that such a device enables detection of Earth-like planets under realistic conditions. Conclusions. The parametric study of the technique lets us believe it can be implemented quite easily in future instruments dedicated to direct imaging of exoplanets.

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Section: Introductionmentioning

confidence: 99%

Self-coherent camera as a focal plane wavefront sensor: simulations

Galicher

Baudoz

Rousset

et al. 2009

A&A

111

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“…Thus, adaptive optics systems dedicated for highcontrast imagers will play an important role in the terrestrial planet finding missions (Bordé & Traub 2006;Give'on et al 2006;Nishikawa et al 2008). We note that differential imaging techniques can also be used for suppressing the speckle noise (Racine et al 1999;Baba & Murakami 2003;Marois et al 2006;Murakami et al 2006Murakami et al , 2007Zubko et al 2007).…”

Section: Discussionmentioning

confidence: 99%

“…A two-channel coronagraph by using a PBS has been proposed to improve the overall system throughput (Baba & Murakami 2003). In Figure 9, we show a simpler optical design of the two-channel coronagraph.…”

Section: Discussionmentioning

confidence: 99%

Achromatic Eight-Octant Phase-Mask Coronagraph Using Photonic Crystal

Murakami¹,

Nishikawa²,

Yokochi³

et al. 2010

ApJ

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We designed and manufactured a photonic-crystal mask which can be used for an achromatic eight-octant phasemask (EOPM) coronagraph for direct detection of extrasolar planets. Laboratory experiments of the EOPM coronagraph were carried out using two laser light sources as a simulated star (wavelengths of 532 and 633 nm). As a result, we attained high extinction of the simulated starlight in both the wavelengths. Halo intensity levels of about 10 −6 and 10 −7 were achieved at an angular distance of 3 and 13λ/D, respectively. We also discuss several issues, such as an effect of phase aberration on the coronagraphic performance, a transmittance of the proposed EOPM, and a novel two-channel coronagraphic configuration to improve system throughput.

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“…The use of polarization characteristics (e.g. Baba & Murakami 2003) or differential wavelength techniques (e.g. Danchi et al 2003) is one of the candidates to develop high dynamic range optics insensitive to such disturbances.…”

Section: Discussionmentioning

confidence: 99%

Combination of nulling interferometer and modified pupil for observations of exo-planets

Nishikawa¹,

Kotani

Murakami

et al. 2005

A&A

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Abstract. We consider a combination of two techniques, namely the nulling interferometer and halo suppression by modified pupil such as shaped pupils and apodized square apertures, which achieves very high dynamic range, in order to detect faint extra-solar planets around nearby stars. The effects of the nulling interferometer and the modified pupil are independent and in combination hence multiplied. We show that one can achieve higher dynamic range in the case of a resolved star than with either method alone. By numerical simulations, we show that the combination method can achieve dynamic range levels of 10 −10 at 3λ/D. Used alone, the two-telescope interferometer would give the nulling depth of 10 −3 whilst the halo suppression by a shaped aperture would do 10 −7 , with a point-spread-function core radius less than 3λ/D for a shaped aperture. The introduction of the modified pupil has the same effect whether it is made at the entrance apertures of the interferometer or at a re-imaged common pupil plane after the nulling interferometry. From another point of view, a nulling interferometer works as pre-optics in front of any single telescope methods, which reduces the intensity of a resolved source transmitting some uniform wavefront residuals.

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A Method to Image Extrasolar Planets with Polarized Light

Cited by 60 publications

References 20 publications

Self-coherent camera as a focal plane wavefront sensor: simulations

Self-coherent camera as a focal plane wavefront sensor: simulations

Achromatic Eight-Octant Phase-Mask Coronagraph Using Photonic Crystal

Combination of nulling interferometer and modified pupil for observations of exo-planets

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