Optical misalignment sensing and image reconstruction using phase diversity

Paxman, Richard G.; Fienup, James R.

doi:10.1364/josaa.5.000914

Cited by 172 publications

(73 citation statements)

References 8 publications

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“…Gonsalves (1982) proposed an evolution of the phase retrieval technique called phase diversity. It was later, demonstrated that this technique can be successfully applied to multi-aperture instruments (Paxman & Fienup 1988).…”

Section: Co-phasing Methodsmentioning

confidence: 99%

Co-phasing of a diluted aperture synthesis instrument for direct imaging: Experimental demonstration on a temporal hypertelescope

Bouyeron¹,

Delage²,

Grossard³

et al. 2012

A&A

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Context. The diluted aperture synthesis is one of the most promising ways of obtaining direct images with an angular resolution in the milliarcsecond range. By applying apodization techniques to a hypertelescope, it is possible to discriminate between objects with a high contrast in intensity with a reasonable number of telescopes (<10). Aims. To reach such performances, we attempt to develop a co-phasing system capable of stabilizing the optical path differences with an accuracy better than λ/100 RMS. Methods. We propose a method based on a joint use of a sub-aperture piston phase-diversity technique and a genetic algorithm to co-phase a laboratory prototype called a temporal hypertelescope (THT). First, we simulated the behavior of this instrument and inferred the related statistical properties of our co-phasing method. In a second step, we implemented this co-phasing system on our THT prototype. Results. We obtain an experimental stabilization of the optical path differences of about λ/300 RMS over 1000 s. Thanks to this result, we are able to acquire an image of a high-contrast binary system. We also validate that the instrument accurately estimates the object characteristics, i.e. 25 μrad for the angular separation and ΔH = 9.1 magnitude difference between the main star and its companion.

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Section: Co-phasing Methodsmentioning

confidence: 99%

Co-phasing of a diluted aperture synthesis instrument for direct imaging: Experimental demonstration on a temporal hypertelescope

Bouyeron¹,

Delage²,

Grossard³

et al. 2012

A&A

View full text Add to dashboard Cite

show abstract

“…They allow us to retrieve all aberrations on every subaperture from one single focal image. The first estimator is a well-known [21] iterative algorithm normally based on a two-image analysis, which we will further demonstrate to work with only one image. It will also serve as a reference in simulations.…”

Section: Least-square Estimatorsmentioning

confidence: 98%

“…This phasediversity method is usually applied for the phase measurement on extended objects (see Mugnier et al [19] for a recent review of phase diversity). Aberration measurement by phase diversity is now routinely used for the calibration of monolithic instruments [20] and has been extended to MAOTs [21][22][23]. While phase diversity is optically very easy to implement, it requires considerable computing power for real-time correction, as it is most often based on an iterative algorithm.…”

Section: Introductionmentioning

confidence: 99%

Unambiguous phase retrieval as a cophasing sensor for phased array telescopes

et al. 2008

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Cophasing a multiple-aperture optical telescope (MAOT) or optical interferometer requires the knowledge of the tips/tilts and of the differential pistons on its subapertures. In this paper we demonstrate in the case of a point source object that a single focal-plane image is sufficient for MAOT cophasing. Adopting a least-square approach allows us to derive an analytic estimator of the subaperture aberrations, provided that these are small enough (typically for closed-loop operation) and that the pupil is diluted noncentrosymmetric. We then provide the validation of this estimator by simulations as well as a performance comparison with a more conventional iterative algorithm of phase retrieval. Finally, we present the experimental validation of both estimators on a laboratory test bench; our results, especially subnanometric repeatability, demonstrate that focalplane sensors are appropriate for the cophasing of phased array telescopes.

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“…Phase diversity [13][14][15] is a convenient way to determine the phase aberrations of images. Typically, two images are recorded simultaneously, often an in-focus and an out-of-focus image.…”

Section: Phase Diversity and Adaptive Opticsmentioning

confidence: 99%

Extremely fast focal-plane wavefront sensing for extreme adaptive optics

et al. 2012

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We present a promising approach to the extremely fast sensing and correction of small wavefront errors in adaptive optics systems. As our algorithm's computational complexity is roughly proportional to the number of actuators, it is particularly suitable to systems with 10,000 to 100,000 actuators. Our approach is based on sequential phase diversity and simple relations between the point-spread function and the wavefront error in the case of small aberrations. The particular choice of phase diversity, introduced by the deformable mirror itself, minimizes the wavefront error as well as the computational complexity. The method is well suited for highcontrast astronomical imaging of point sources such as the direct detection and characterization of exoplanets around stars, and it works even in the presence of a coronagraph that suppresses the diffraction pattern. The accompanying paper in these proceedings by Korkiakoski et al. describes the performance of the algorithm using numerical simulations and laboratory tests.

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Optical misalignment sensing and image reconstruction using phase diversity

Cited by 172 publications

References 8 publications

Co-phasing of a diluted aperture synthesis instrument for direct imaging: Experimental demonstration on a temporal hypertelescope

Co-phasing of a diluted aperture synthesis instrument for direct imaging: Experimental demonstration on a temporal hypertelescope

Unambiguous phase retrieval as a cophasing sensor for phased array telescopes

Extremely fast focal-plane wavefront sensing for extreme adaptive optics

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