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extreme adaptive optics; high order wavefront sensing; Mach-Zehnder interferometer; high dynamic range; spatial light modulator; deformable mirror
Abstract :
[en] Extreme adaptive optics (XAO) encounters severe difficulties to cope with the high speed (>1kHz), high accuracy and high order requirements for future extremely large telescopes. An innovative high order adaptive optics system using a self-referenced Mach-Zehnder wavefront sensor (MZWFS) allows counteracting these limitations. This sensor estimates very accurately the wavefront phase at small spatial scale by measuring intensity differences between two outputs, with a λ/4 path length difference between its two legs, but is limited in dynamic range due to phase ambiguity. During the past few years, such an XAO system has been studied by our team in the framework of 8-meter class telescopes. In this work, we report on our latest results with the XAO testbed recently installed in our lab, and dedicated to high contrast imaging with 30m-class telescopes (such as the E-ELT or the TMT). After reminding the principle of a MZWFS and describing the optical layout of our experiment, we will show the results of the assessment of the woofer-tweeter phase correctors, i.e., a Boston Micromachine continuous membrane deformable mirror (DM) and a Boulder Nonlinear Systems liquid crystal spatial light modulator (SLM). In particular, we will detail the calibration of the DM using Zygo interferometer metrology. Our method consists in the precise measurement of the membrane deformation while applying a constant deformation to 9 out of 140 actuators at the same time. By varying the poke voltage across the DM operating range, we propose a simple but efficient way of modeling the DM influence function using a Gaussian model. Finally, we show the DM flattening on the MZWFS allowing to compensate for low order aberrations. This work is carried out in synergy with the validation of fast iterative wavefront reconstruction algorithms, and the optimal treatment of phase ambiguities in order to mitigate the dynamical range limitation of such an MZWFS.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Delacroix, Christian ; Université Claude Bernard - Lyon 1 - UCLB > Centre de Recherche Astrophysique de Lyon (CRAL)
Langlois, Maud; Université Claude Bernard - Lyon 1 - UCLB > Centre de Recherche Astrophysique de Lyon (CRAL)
Loupias, Magali; Université Claude Bernard - Lyon 1 - UCLB > Centre de Recherche Astrophysique de Lyon (CRAL)
Thiébaut, Eric; Université Claude Bernard - Lyon 1 - UCLB > Centre de Recherche Astrophysique de Lyon (CRAL)
Adjali, Louisa; Université Claude Bernard - Lyon 1 - UCLB > Centre de Recherche Astrophysique de Lyon (CRAL)
Leger, Jonathan; Université Claude Bernard - Lyon 1 - UCLB > Centre de Recherche Astrophysique de Lyon (CRAL)
Tallon, Michel; Université Claude Bernard - Lyon 1 - UCLB > Centre de Recherche Astrophysique de Lyon (CRAL)
Language :
English
Title :
Development of an ELT XAO testbed using a Mach-Zehnder wavefront sensor: calibration of the deformable mirror
Hinkley, S., Oppenheimer, B. R., Zimmerman, N., et al., "A New High Contrast Imaging Program at Palomar Observatory, " PASP 123, 74 (2011).
Macintosh, B., Graham, J. R., Ingraham, P., et al., "The Gemini Planet Imager: First Light, " PNAS 111, 12661-12666 (2014).
Beuzit, J., Feldt, M., Dohlen, K., et al., "SPHERE: A planet finder instrument for the VLT, " Proc. SPIE 7014, 701418-12 (2008).
Mawet, D., Pueyo, L., Lawson, P., et al., "Review of small-Angle coronagraphic techniques in the wake of ground-based second-generation adaptive optics systems, " Proc. SPIE 8442, 84204 (2012).
Fusco, T., Sauvage, J.-F., Petit, C., et al., "Final performance and lesson-learned of SAXO, the VLT-SPHERE eXtreme AO: from early design to on-sky results, " Proc. SPIE 9148, 91481U-15 (2014).
Guyon O., "Limits of Adaptive Optics for High-Contrast Imaging, " ApJ 629, 592-614 (2005).
Angel, J. R. P., "Ground-based imaging of extrasolar planets using adaptive optics, " Nature 368, 203 (1994).
Langlois, M., Angel, J. R. P., Lloyd-Hart, M., et al., "High Order, Reconstructor-Free Adaptive Optics for 6-8 meter class Telescopes, " Proc. Beyond Conv. AO 58, 113-120 (2001).
Dohlen, K., "Phase masks in astronomy: From the Mach-Zehnder interferometer to coronagraphs, " EAS Publications Series 12, 33-44 (2004).
Zernike, F. "Diffraction Theory of the Knife-Edge Test and its Improved Form, the Phase-Contrast Method, " MNRAS 94, 377 (1934).
Bloemhof, E. E., & Wallace J. K., "Phase contrast techniques for wavefront sensing and calibration in adaptive optics, " Proc. SPIE 5169, 309-320 (2003).
Ragazzoni, R., "Pupil plane wave-front sensing with an oscillating prism, " J. Mod. Opt. 43, 289-293 (1996).
Brandl, B. R., Feldt, M., Glasse, A., et al., "METIS: The mid-infrared E-ELT imager and spectrograph, " Proc. SPIE 9147, 914721-18 (2014).
Delacroix, C., Absil, O., Forsberg, P., et al., "Laboratory demonstration of a mid-infrared AGPM vector vortex coronagraph, " A&A 553, A98 (2013).
Mawet, D., Absil, O., Delacroix, C., et al., "L'-band AGPM vector vortex coronagraph's first light on VLT/NACO-Discovery of a late-Type companion at two beamwidths from an F0V star, " A&A 552, L13 (2013).
Delacroix, C., Absil, O., Mawet, D., et al., "A diamond AGPM coronagraph for VISIR, " Proc. SPIE 8446, 84468K (2012).
Kerber, F., Käufl, H.-U., Baksai, P., et al., "VISIR upgrade overview and status, " Proc. SPIE 9147, 91470C (2014).
Defrère, D., Absil, O., Hinz, P., et al., "L'-band AGPM vector vortex coronagraph's first light on LBTI/LMIRCAM, " Proc. SPIE 9148, 145 (2014).
Jovanovic, N., Guyon, O., Martinache, F., et al., "How to inject light efficiently into single-mode fibers, " 2014, Proc. SPIE 9147, 91477P (2014).
Huby, E., Baudoz, P., Mawet, D., et al., "Post-coronagraphic tip-Tilt sensing for vortex phase masks: The QACITS technique, " A&A (2015 in press).
Langlois, M., Pasanau, C., Leroux, B., et al., "Progress with extreme adaptive optics test bench for ELT at LAM, " Proc. SPIE 7015, 701544 (2008).
Guzmán, D., de Cos Juez, F. J., Sánchez Lasheras F., et al., "Deformable mirror model for open-loop adaptive optics using multivariate adaptive regression splines, " Opt. Express 18, 6492-6505 (2010).
Shaw, M., Hall, S., Knox, S., et al., "Characterization of deformable mirrors for spherical aberration correction in optical sectioning microscopy, " Opt. Express 18, 6900-6913 (2010).
Lane, R. G., and Tallon, M., "Wave-front reconstruction using a Shack-Hartmann sensor, " Appl. Opt. 31, 6902-6908 (1992).
Tallon, M., Tallon-Bosc, I., Béchet, C., et al., "Fractal iterative method for fast atmospheric tomography on extremely large telescopes, " Proc. SPIE 7736, 77360X (2010).
Rigaut, F., Ellerbroek, B.L., and Northcott, M.J., "Comparison of curvature-based and Shack-Hartmann-based adaptive optics for the Gemini telescope, " Appl. Opt. 36, 13 (1997).
Baker, K. L., "Interferometric wavefront sensors for high contrast imaging, " Opt. Express 14, 10970-10975 (2006).