Abstract

We present a design improvement for a recently proposed type of Shack–Hartmann wavefront sensor that uses a cylindrical (lenticular) lenslet array. The improved sensor design uses optical binning and requires significantly fewer detector pixels than the corresponding conventional or cylindrical Shack–Hartmann sensor, and so detector readout noise causes less signal degradation. Additionally, detector readout time is significantly reduced, which reduces the latency for closed loop systems and data processing requirements. We provide simple analytical noise considerations and Monte Carlo simulations, we show that the optically binned Shack–Hartmann sensor can offer better performance than the conventional counterpart in most practical situations, and our design is particularly suited for use with astronomical adaptive optics systems.

© 2007 Optical Society of America

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References

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  1. M. Ares, S. Royo, and J. Caum, "Shack-Hartmann sensor based on a cylindrical microlens array," Opt. Lett. 32, 769-771 (2007).
    [CrossRef] [PubMed]
  2. R. M. Myers, A. J. Longmore, C. R. Benn, D. F. Buscher, P. Clark, N. A. Dipper, N. Doble, A. P. Doel, C. N. Dunlop, X. Gao, T. Gregory, R. A. Humphreys, D. J. Ives, R. Øestensen, P. T. Peacocke, R. G. Rutten, C. J. Tierney, A. J. A. Vick, M. R. Wells, R. W. Wilson, S. P. Worswick, and A. Zadrozny, "NAOMI adaptive optics system for the 4.2 m William Herschel telescope," in Adaptive Optical System Technologies II, P. L. Wizinowich and D. Bonaccini, eds., Proc. SPIE 4839, 647-658 (2003).
    [CrossRef]
  3. H. T. Barclay, P. H. Malyak, W. H. McGonagle, R. K. Reich, G. S. Rowe, and J. C. Twichell, "The SWAT wavefront sensor," Lincoln Lab. J. 5, 115-130 (1992).
  4. L. E. Schmutz, J. K. Bowker, J. Feinleib, and S. Tubbs, "Integrated imaging irradiance (I3) sensor: a new method for real-time wavefront mensuration," in Adaptive Optical Components II, S. Holly and L. James, eds., Proc. SPIE 141, 120-124 (1979).
  5. S. Thomas, T. Fusco, A. Tokovinin, M. Nicolle, V. Michau, and G. Rousset, "Comparison of centroid computation algorithms in a Shack-Hartmann sensor," Mon. Not. R. Astron. Soc. 371, 323-336 (2006).
    [CrossRef]
  6. A. G. Basden, T. Butterley, R. M. Myers, and R. W. Wilson, "Durham extremely large telescope adaptive optics simulation platform," Appl. Opt. 46, 1089-1098 (2007).
    [CrossRef] [PubMed]
  7. G. I. Taylor, "The spectrum of turbulence," Proc. R. Soc. London Ser. A 164, 476-490 (1938).
    [CrossRef]
  8. C. R. Benn, M. Blanken, C. Bevil, S. Els, S. Goodsell, T. Gregory, P. Jolley, A. J. Longmore, O. Martin, R. M. Myers, R. Ostensen, S. Rees, R. G. M. Rutten, I. Soechting, G. Talbot, and S. M. Tulloch, "NAOMI: adaptive optics at the WHT," in Advancements in Adaptive Optics, D. B. Calia, B. L. Ellerbroek, and R. Ragazzoni, Proc. SPIE 5490, 79-89 (2004).
    [CrossRef]

2007

2006

S. Thomas, T. Fusco, A. Tokovinin, M. Nicolle, V. Michau, and G. Rousset, "Comparison of centroid computation algorithms in a Shack-Hartmann sensor," Mon. Not. R. Astron. Soc. 371, 323-336 (2006).
[CrossRef]

2004

C. R. Benn, M. Blanken, C. Bevil, S. Els, S. Goodsell, T. Gregory, P. Jolley, A. J. Longmore, O. Martin, R. M. Myers, R. Ostensen, S. Rees, R. G. M. Rutten, I. Soechting, G. Talbot, and S. M. Tulloch, "NAOMI: adaptive optics at the WHT," in Advancements in Adaptive Optics, D. B. Calia, B. L. Ellerbroek, and R. Ragazzoni, Proc. SPIE 5490, 79-89 (2004).
[CrossRef]

2003

R. M. Myers, A. J. Longmore, C. R. Benn, D. F. Buscher, P. Clark, N. A. Dipper, N. Doble, A. P. Doel, C. N. Dunlop, X. Gao, T. Gregory, R. A. Humphreys, D. J. Ives, R. Øestensen, P. T. Peacocke, R. G. Rutten, C. J. Tierney, A. J. A. Vick, M. R. Wells, R. W. Wilson, S. P. Worswick, and A. Zadrozny, "NAOMI adaptive optics system for the 4.2 m William Herschel telescope," in Adaptive Optical System Technologies II, P. L. Wizinowich and D. Bonaccini, eds., Proc. SPIE 4839, 647-658 (2003).
[CrossRef]

1992

H. T. Barclay, P. H. Malyak, W. H. McGonagle, R. K. Reich, G. S. Rowe, and J. C. Twichell, "The SWAT wavefront sensor," Lincoln Lab. J. 5, 115-130 (1992).

1979

L. E. Schmutz, J. K. Bowker, J. Feinleib, and S. Tubbs, "Integrated imaging irradiance (I3) sensor: a new method for real-time wavefront mensuration," in Adaptive Optical Components II, S. Holly and L. James, eds., Proc. SPIE 141, 120-124 (1979).

1938

G. I. Taylor, "The spectrum of turbulence," Proc. R. Soc. London Ser. A 164, 476-490 (1938).
[CrossRef]

Appl. Opt.

Lincoln Lab. J.

H. T. Barclay, P. H. Malyak, W. H. McGonagle, R. K. Reich, G. S. Rowe, and J. C. Twichell, "The SWAT wavefront sensor," Lincoln Lab. J. 5, 115-130 (1992).

Mon. Not. R. Astron. Soc.

S. Thomas, T. Fusco, A. Tokovinin, M. Nicolle, V. Michau, and G. Rousset, "Comparison of centroid computation algorithms in a Shack-Hartmann sensor," Mon. Not. R. Astron. Soc. 371, 323-336 (2006).
[CrossRef]

Opt. Lett.

Proc. R. Soc. London Ser. A

G. I. Taylor, "The spectrum of turbulence," Proc. R. Soc. London Ser. A 164, 476-490 (1938).
[CrossRef]

Proc. SPIE

C. R. Benn, M. Blanken, C. Bevil, S. Els, S. Goodsell, T. Gregory, P. Jolley, A. J. Longmore, O. Martin, R. M. Myers, R. Ostensen, S. Rees, R. G. M. Rutten, I. Soechting, G. Talbot, and S. M. Tulloch, "NAOMI: adaptive optics at the WHT," in Advancements in Adaptive Optics, D. B. Calia, B. L. Ellerbroek, and R. Ragazzoni, Proc. SPIE 5490, 79-89 (2004).
[CrossRef]

L. E. Schmutz, J. K. Bowker, J. Feinleib, and S. Tubbs, "Integrated imaging irradiance (I3) sensor: a new method for real-time wavefront mensuration," in Adaptive Optical Components II, S. Holly and L. James, eds., Proc. SPIE 141, 120-124 (1979).

R. M. Myers, A. J. Longmore, C. R. Benn, D. F. Buscher, P. Clark, N. A. Dipper, N. Doble, A. P. Doel, C. N. Dunlop, X. Gao, T. Gregory, R. A. Humphreys, D. J. Ives, R. Øestensen, P. T. Peacocke, R. G. Rutten, C. J. Tierney, A. J. A. Vick, M. R. Wells, R. W. Wilson, S. P. Worswick, and A. Zadrozny, "NAOMI adaptive optics system for the 4.2 m William Herschel telescope," in Adaptive Optical System Technologies II, P. L. Wizinowich and D. Bonaccini, eds., Proc. SPIE 4839, 647-658 (2003).
[CrossRef]

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Figures (8)

Fig. 1
Fig. 1

Conventional Shack–Hartmann wavefront sensor and a typical spot pattern with 64 subapertures (4096 detector pixels).

Fig. 2
Fig. 2

(a) Optically binned Shack–Hartmann wavefront sensor. The incoming wavefront is split using a beam splitter, and each beam then passes through orthogonal cylindrical lenslet arrays, to record the x and y wavefront gradients on separate detectors. (b) A typical resulting image from detector 1 (512 detector pixels, 8 × 8 subapertures, vertical lenslet array). (c) A typical resulting image from detector 2 (512 detector pixels, 8 × 8 subapertures, horizontal lenslet array). Elongated rectangular detector pixels have been used in (b) and (c) to make the image clearer.

Fig. 3
Fig. 3

Possible subdesigns for an optically binned Shack–Hartmann sensor, (a) using fold mirrors to rotate the reflected beam by 90° and (b) using shared cylindrical optics for each beam, one beam shown, to compress the phase in one dimension relative to the other.

Fig. 4
Fig. 4

Components of a Monte Carlo simulation used to compare wavefront sensor performance. A simulated beam splitter is used to direct half the light to a conventional AO and imaging system, while the other half is directed to an optically binned AO system. The performances of these systems can then be directly compared.

Fig. 5
Fig. 5

Relative performance between a conventional and an optically binned SHS as a function of source magnitude. The inset shows the FWHM as a function of magnitude.

Fig. 6
Fig. 6

Relative performance between a conventional and an optically binned SHS as a function of detector readout noise. Inset shows the results for 0–1 electron readout noise in more detail.

Fig. 7
Fig. 7

Relative performance between a conventional and an optically binned SHS as a function of the linear number of subapertures.

Fig. 8
Fig. 8

Dependence on relative performance between a conventional and optically binned SHS with the number of pixels per subaperture (linear dimension, so for the conventional case, the total number is this squared, while for the optically binned case, the total number is this multiplied by two).

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