Multi-axial nulling interferometry: demonstration of deep nulling and investigations of polarization effects

Buisset, Christophe; Rejeaunier, Xavier; Rabbia, Yves; Ruilier, Cyril; Barillot, Marc; Lierstuen, Lars; Armengol, Josep Maria Perdigués

doi:10.1117/12.671113

Cited by 8 publications

(6 citation statements)

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“…Such a sum can be achieved in an elegant and simple way thanks to a single-mode fiber optics. The efficiency of this cancelling device has actually been demonstrated (e.g., Wallner et al 2004;Buisset et al 2006). To obtain A(−u, v) = A(u, v), and because the sin(πuD) function is odd, it is sufficient to make sure that Sum (e jπPΛ − e jπQΛ ) · expUV(u, v) is even.…”

Section: The Multi-axial Chessboardsmentioning

confidence: 99%

The achromatic chessboard, a new concept of a phase shifter for nulling interferometry

Pelat

Rouan

Pickel

2010

A&A

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Context. Nulling interferometry in the mid-IR using two telescopes (commonly referred to a Bracewell interferometer) is one possible way of directly detecting exoplanets in the habitable zone and their characterisation in terms of possible life signatures. A large wavelength domain is needed to simultaneously detect the infrared spectral features of a set of a bio-tracers. An achromatic phase shift of π is then required, and we previously presented a new concept for such a function that allows a simple design with only one device per beam. It is based on two cellular mirrors, called the chessboards, where each cell has a thickness that introduces, for any given central wavelength, a phase shift of (2k + 1)π or of 2kπ on the fraction of the wave it reflects. Aims. We explore a more rigorous way to establish the optimum cell pattern design to attain the best theoretical performances for planet detection over a broad wavelength range. Two possible types of interferometres are now considered: on-axis and multi-axis. Methods. We derived a rather simple iterative scheme for both designs, determining the thickness and XY position of the cells. The method confers to the chessboards a high degree of internal symmetry. Each design can be described as an iterative Bracewell interferometer characterised by an integer order. We demonstrate that their efficiencies increases with the power of that order. Results. The device acts both spatially and versus wavelengths as an optical differential operator on the 3D light distribution. Its power is best understood in the on-axis case since its effect is to push away the stellar light from the centre over a very broad range of wavelengths, leaving space for an out of phase object to appear in the cleaned central region. We explore the theoretical performances for on-axis and multi-axis designs in the parameter space, and we especially compute the rejection factor for starlight and the attenuation factor for planet light and introduce the relative nulling efficiency metric. We show that, even with some realistic piston error added, the performances could meet the Darwin space project specifications for both designs, i.e., cancellation of the starlight by a factor of 10 5 over a wavelength range of 6-17 μm.

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Section: The Multi-axial Chessboardsmentioning

confidence: 99%

The achromatic chessboard, a new concept of a phase shifter for nulling interferometry

Pelat

Rouan

Pickel

2010

A&A

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“…The work by other researchers in the field should not be overlooked, and details of some of the nulling results achieved elsewhere can be found in references [10], [11] & [12].…”

Section: Nulling Resultsmentioning

confidence: 97%

Starlight Nulling Technology at the Jet Propulsion Laboratory

Martin

2007

2007 IEEE Aerospace Conference

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The current interests in extra-solar planet detection and space-based and ground-based interferometry for astronomical observations have led to the development of a number of nulling instruments at the Jet Propulsion Laboratory (JPL) and elsewhere. This paper 12 summarizes briefly JPL's efforts in nulling interferometry to date and consists of illustrations of some key nulling technologies. The basic optical layouts of instruments demonstrating three different nulling techniques are shown. In an effort to narrow the area of discussion, some notable nulling efforts made elsewhere will not be included.

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“…done at the image plane level and not at the pupil level, could also be considered, with the advantage of keeping the design fully symmetric. It has been shown (e.g., Buisset et al 2006;Wallner et al 2004) that nulling is as efficient with this design as in a more classical co-axial recombination (Michelson type), provided that the star image (i.e. the PSF) is formed on single-mode fiber optics that will make the overlap integral of the product between the incident electric fields and the fundamental mode distribution of the fiber.…”

Section: The Concept Of the Chessboard Phase Shiftermentioning

confidence: 99%

The achromatic chessboard, a new concept of a phase shifter for nulling interferometry

Rouan¹,

Pelat²

2008

A&A

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Context. Direct detection of a planet around a star and its characterisation for identification of bio-tracers in the mid-IR requires a nulling interferometer. Such an instrument must be efficient in a large wavelength domain in order to have the capability of simultaneously detecting the infrared spectral features of several bio-tracers: CO 2 , O 3 , and H 2 O. Aims. A broad wavelength range can be effective provided that an achromatic phase shift of π can be implemented, with good enough accuracy to achieve a deep nulling at all considered wavelengths. A new design concept for such an achromatic phase shifter is presented here. The major interest of this solution is that it allows a simple design with only one device per beam. Methods. The heart of the system consists in two cellular mirrors where each cell has a thickness that introduces, for a given central wavelength, a phase shift of (2k + 1)π or of 2kπ on the fraction of the wave it reflects. Each mirror is put in one of the collimated beams of the interferometer. Because of the odd/even distribution, a destructive interference is produced on axis for the central wavelength when recombining the two beams. If the number of cells of a given thickness follows a rather simple law based on the Pascal's triangle, we then show that the nulling is also efficient for a wavelength that is not too far from the central wavelength.Results. The effect of achromatization is more efficient the more cells there are. For instance, with two mirrors of 64 × 64 cells, where the cells' phase shift ranges between −6π and +6π, one reaches a nulling of 10 −6 on a wavelength range [0.6λ 0 , 1.25λ 0 ], i.e. on more than one complete octave. This is why we claim that this device produces a quasi-achromatic phase shift ; especially, it could satisfy the specifications of a space mission as DARWIN. In a second step, we study the optimum way to distribute the cells in the plane of the pupil. The most important criterion is the isolation of the planet image from the residual image of the star. Several algorithms and their nulling performances are presented.

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Multi-axial nulling interferometry: demonstration of deep nulling and investigations of polarization effects

Cited by 8 publications

References 1 publication

The achromatic chessboard, a new concept of a phase shifter for nulling interferometry

The achromatic chessboard, a new concept of a phase shifter for nulling interferometry

Starlight Nulling Technology at the Jet Propulsion Laboratory

The achromatic chessboard, a new concept of a phase shifter for nulling interferometry

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