Open-loop control of SCExAO's MEMS deformable mirror using the Fast Iterative Algorithm: Speckle control performances

Célia Blain, Olivier Guyon, Frantz Martinache, Colin Bradley, Christophe Clergeon

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Micro-Electro-Mechanical Systems (MEMS) deformable mirrors (DMs) are widely utilized in astronomical Adaptive Optics (AO) instrumentation. High precision open-loop control of MEMS DMs has been achieved by developing a high accuracy DM model, the Fast Iterative Algorithm (FIA), a physics-based model allowing precise control of the DM shape. Accurate open-loop control is particularly critical for the wavefront control of High-Contrast Imaging (HCI) instruments to create a dark hole area free of most slow and quasi-static speckles which remain the limiting factor for direct detection and imaging of exoplanets. The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system is one of these high contrast imaging instruments and uses a 1024-actuator MEMS deformable mirror (DM) both in closed-loop and open-loop. The DM is used to modulate speckles in order to distinguish (i) speckles due to static and slow-varying residual aberrations from (ii) speckles due to genuine structures, such as exoplanets. The FIA has been fully integrated into the SCExAO wavefront control software and we report the FIA's performance for the control of speckles in the focal plane.

Original languageEnglish (US)
Title of host publicationAdaptive Optics Systems III
StatePublished - 2012
EventAdaptive Optics Systems III - Amsterdam, Netherlands
Duration: Jul 1 2012Jul 6 2012

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherAdaptive Optics Systems III


  • Adaptive optics
  • Deformable mirrors
  • Focal plane speckle control
  • High-contrast imaging
  • Open-loop control

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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