Abstract

Exoplanet direct imaging is a challenging goal of today’s astronomical instrumentation. Several high-contrast imaging instruments dedicated to this task are currently being integrated; they are ultimately limited by the presence of quasi-static speckles in the imaging focal plane. These speckles originate in residual quasi-static optical aberrations, which must be measured and compensated for, typically at a nanometric level. We present a novel focal plane wavefront sensor (WFS) designed for this particular application. It is an extension of the phase diversity technique to coronagraphic imaging. This sensor requires no dedicated hardware and uses only two scientific images differing from a known aberration, which can be conveniently introduced by the adaptive optics subsystem. The aberrations are therefore calibrated all the way down to the scientific camera, without any differential aberrations between the sensor and the scientific camera. We show the potential of this WFS by means of simulations, and we perform a preliminary experimental validation.

© 2012 Optical Society of America

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References

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  1. J.-L. Beuzit, M. Feldt, K. Dohlen, D. Mouillet, P. Puget, and F. Wildi, Proc. SPIE 7014, 1 (2008).
  2. M. Mas, P. Baudoz, G. Rousset, R. Galicher, and J. Baudrand, Proc. SPIE 7735, 773566 (2010).
    [CrossRef]
  3. A. Give’on, R. Belikov, S. Shaklan, and J. Kasdin, Opt. Express 15, 12338 (2007).
    [CrossRef]
  4. J.-F. Sauvage, L. M. Mugnier, G. Rousset, and T. Fusco, J. Opt. Soc. Am. A 27, A157 (2010).
  5. L. M. Mugnier, A. Blanc, and J. Idier, Advances in Imaging and Electron Physics, P. Hawkes, ed. (Elsevier, 2006), Chap. 1, pp. 1–76.
  6. F. Roddier and C. Roddier, Pub. Astron. Soc. Pac. 109, 815 (1997).
    [CrossRef]

2010

M. Mas, P. Baudoz, G. Rousset, R. Galicher, and J. Baudrand, Proc. SPIE 7735, 773566 (2010).
[CrossRef]

J.-F. Sauvage, L. M. Mugnier, G. Rousset, and T. Fusco, J. Opt. Soc. Am. A 27, A157 (2010).

2008

J.-L. Beuzit, M. Feldt, K. Dohlen, D. Mouillet, P. Puget, and F. Wildi, Proc. SPIE 7014, 1 (2008).

2007

1997

F. Roddier and C. Roddier, Pub. Astron. Soc. Pac. 109, 815 (1997).
[CrossRef]

Baudoz, P.

M. Mas, P. Baudoz, G. Rousset, R. Galicher, and J. Baudrand, Proc. SPIE 7735, 773566 (2010).
[CrossRef]

Baudrand, J.

M. Mas, P. Baudoz, G. Rousset, R. Galicher, and J. Baudrand, Proc. SPIE 7735, 773566 (2010).
[CrossRef]

Belikov, R.

Beuzit, J.-L.

J.-L. Beuzit, M. Feldt, K. Dohlen, D. Mouillet, P. Puget, and F. Wildi, Proc. SPIE 7014, 1 (2008).

Blanc, A.

L. M. Mugnier, A. Blanc, and J. Idier, Advances in Imaging and Electron Physics, P. Hawkes, ed. (Elsevier, 2006), Chap. 1, pp. 1–76.

Dohlen, K.

J.-L. Beuzit, M. Feldt, K. Dohlen, D. Mouillet, P. Puget, and F. Wildi, Proc. SPIE 7014, 1 (2008).

Feldt, M.

J.-L. Beuzit, M. Feldt, K. Dohlen, D. Mouillet, P. Puget, and F. Wildi, Proc. SPIE 7014, 1 (2008).

Fusco, T.

Galicher, R.

M. Mas, P. Baudoz, G. Rousset, R. Galicher, and J. Baudrand, Proc. SPIE 7735, 773566 (2010).
[CrossRef]

Give’on, A.

Idier, J.

L. M. Mugnier, A. Blanc, and J. Idier, Advances in Imaging and Electron Physics, P. Hawkes, ed. (Elsevier, 2006), Chap. 1, pp. 1–76.

Kasdin, J.

Mas, M.

M. Mas, P. Baudoz, G. Rousset, R. Galicher, and J. Baudrand, Proc. SPIE 7735, 773566 (2010).
[CrossRef]

Mouillet, D.

J.-L. Beuzit, M. Feldt, K. Dohlen, D. Mouillet, P. Puget, and F. Wildi, Proc. SPIE 7014, 1 (2008).

Mugnier, L. M.

J.-F. Sauvage, L. M. Mugnier, G. Rousset, and T. Fusco, J. Opt. Soc. Am. A 27, A157 (2010).

L. M. Mugnier, A. Blanc, and J. Idier, Advances in Imaging and Electron Physics, P. Hawkes, ed. (Elsevier, 2006), Chap. 1, pp. 1–76.

Puget, P.

J.-L. Beuzit, M. Feldt, K. Dohlen, D. Mouillet, P. Puget, and F. Wildi, Proc. SPIE 7014, 1 (2008).

Roddier, C.

F. Roddier and C. Roddier, Pub. Astron. Soc. Pac. 109, 815 (1997).
[CrossRef]

Roddier, F.

F. Roddier and C. Roddier, Pub. Astron. Soc. Pac. 109, 815 (1997).
[CrossRef]

Rousset, G.

J.-F. Sauvage, L. M. Mugnier, G. Rousset, and T. Fusco, J. Opt. Soc. Am. A 27, A157 (2010).

M. Mas, P. Baudoz, G. Rousset, R. Galicher, and J. Baudrand, Proc. SPIE 7735, 773566 (2010).
[CrossRef]

Sauvage, J.-F.

Shaklan, S.

Wildi, F.

J.-L. Beuzit, M. Feldt, K. Dohlen, D. Mouillet, P. Puget, and F. Wildi, Proc. SPIE 7014, 1 (2008).

J. Opt. Soc. Am. A

Opt. Express

Proc. SPIE

J.-L. Beuzit, M. Feldt, K. Dohlen, D. Mouillet, P. Puget, and F. Wildi, Proc. SPIE 7014, 1 (2008).

M. Mas, P. Baudoz, G. Rousset, R. Galicher, and J. Baudrand, Proc. SPIE 7735, 773566 (2010).
[CrossRef]

Pub. Astron. Soc. Pac.

F. Roddier and C. Roddier, Pub. Astron. Soc. Pac. 109, 815 (1997).
[CrossRef]

Other

L. M. Mugnier, A. Blanc, and J. Idier, Advances in Imaging and Electron Physics, P. Hawkes, ed. (Elsevier, 2006), Chap. 1, pp. 1–76.

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Figures (2)

Fig. 1.
Fig. 1.

Criterion J to be minimized as a function of the phase parameters (a4,a5), for an amplitude of the true phase equal to 0.1 rad. (Left) The diversity is focus only ϕdiv=0.8Z4. (Right) The diversity is a mix of defocus and astigmatism with ϕdiv=0.8Z4+0.8Z5. In both maps, a4 and a5 range from 2 to +2rad.

Fig. 2.
Fig. 2.

(Bottom) Noisy simulated RRPM focal images and (top) images reconstructed from the estimated aberrations. (Left) Focused and (right) phase-diverse images in logarithmic scale. The simulation accounts for a 2×106 photon star, photon and 1e Read-out noise (RON), a perfect RRPM coronagraph, 0.3 rad upstream, 0.1 rad downstream RMS wave-front error (WFE), and a mixed diversity phase.

Tables (1)

Tables Icon

Table 1. Introduced Tilt Values and Their Estimation by COFFEE from a Pair of Experimental Images

Equations (5)

Equations on this page are rendered with MathJax. Learn more.

ifc=f·hdhc(ϕup,ϕdown)+n,
idc=f·hdhc(ϕup+ϕdiv,ϕdown)+n,
(f^,ϕ^up,ϕ^down)=argminf,ϕup,ϕdownJ(f,ϕup,ϕdown),
J(f,ϕup,ϕdown)=12ifcf·hdhc(ϕup,ϕdown)σn2+12idcf·hdhc(ϕup+ϕdiv,ϕdown)σn2+R(ϕup)+R(ϕdown),
J(ϕup,ϕdown)=J(f^(ϕup,ϕdown),ϕup,ϕdown).

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