Abstract

In this article we present a downscaled laboratory setup emulating five natural guide stars, a layered static atmosphere and a 7.5-m aperture telescope equipped with dual-conjugate adaptive optics at a wavelength of 2.2 µm. Three reconstruction alternatives were evaluated; conventional adaptive optics, field-averaged conventional adaptive optics and dual-conjugate adaptive optics. The results were compared with Zemax-simulations of the setup. The expected increase of the size of the isoplanatic patch, using dual-conjugate adaptive optics, was confirmed.

© 2003 Optical Society of America

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References

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    [CrossRef]
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    [CrossRef] [PubMed]
  9. J. W. Hardy, Adaptive Optics for Astronomical Telescopes (Oxford University Press, Oxford, UK, 1998).

Annu. Rev. Astron. Astrophys.

J. M. Beckers, �??Adaptive Optics for Astronomy: Principles, Performance and Applications,�?? Annu. Rev. Astron. Astrophys. 31, 13-62 (1993).
[CrossRef]

Astron. Astrophys.

R. Foy and A. Labeyrie, �??Feasibility of adaptive telescope with laser probe,�?? Astron. Astrophys. 152, L29-L31 (1985).

ESO symposium on Large Telescopes

J. M. Beckers, �??Increasing the size of the isoplanatic patch with multiconjugate adaptive optics,�?? in ESO symposium on Large Telescopes and Their Instrumentation (European Southern Observatory, Garching, Germany, 1988), 693-703.

J. Opt. Soc. Am. A

Opt. Express

Proc. SPIE

R. Flicker, F. Rigaut and B. Ellerbroek, �??Comparison of multiconjugate adaptive optics configurations and control algorithms for the Gemini-South 8-m telescope,�?? in Adaptive Optical Systems Technology, P. Wizinowich, ed., Proc. SPIE 4007, 1032-1043 (2000).
[CrossRef]

Other

J. W. Hardy, Adaptive Optics for Astronomical Telescopes (Oxford University Press, Oxford, UK, 1998).

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Figures (4)

Fig. 1.
Fig. 1.

Schematic birds eye view of the optical setup, with rays originating from the central GS.

Fig. 2.
Fig. 2.

a) Sample of optical path difference from PS2 given in radians, with distance r scaled to parent version. b) Obtained structure function DΦ from PS2, averaging over 10 measurements (blue) compared to the Kolmogorov structure function DΦ=k·r5/3 (green).

Fig. 3.
Fig. 3.

Average PSFs from the experiment. Case a) is uncorrected, b) is corrected with conventional AO, c) is field averaged conventional AO and d) is dual-conjugate AO. The intensity IN is normalised with the central intensity of the diffraction-limited PSF. The axes of the PSFs are the relative coordinates in arc seconds, scaled to the parent version.

Fig. 4.
Fig. 4.

Comparison of the experimental results with a Zemax model of the experiment. The black curves depict the Strehl ratio as function of angle, α, from the central guide star in the parent experiment with error intervals marked in green or blue. The red dots are the experimental values including error bars. Case a) is uncorrected, b) is corrected with conventional AO, c) is field averaged conventional AO and d) is dual-conjugate AO. The green families resulted from running the optimization routine a single time, and the blue family resulted from running it 10 times. See text for more explanation.

Tables (2)

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Table 1. Scaling of the atmosphere in the experiment

Tables Icon

Table 2. Key parameters for the experiment, and scaled to parent version.

Equations (5)

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α exp = C · α par .
σ α 2 = 0.364 λ 2 D 1 3 r 0 5 3 ,
s = G c ,
[ s 1 s 2 s 3 s 4 s 5 ] = G [ c 1 c 2 ] , where G = [ s 1 c 1 s 1 c 2 s 2 c 1 s 2 c 2 s 3 c 1 s 3 c 2 s 4 c 1 s 4 c 2 s 5 c 1 s 5 c 2 ] .
β par = f L 1 f L 2 λ par λ exp D exp D par β exp ,

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