A Novel Hexpyramid Pupil Slicer for an ExAO Parallel DM for the Giant Magellan Telescope

Maggie Kautz, Laird M. Close, Alex Hedglen, Sebastiaan Haffert, Jared R. Males, Fernando Coronado

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

5 Scopus citations


The 25.4m Giant Magellan Telescope (GMT) will be amongst the first in a new series of segmented extremely large telescopes (ELTs). The 25.4 m pupil is segmented into seven 8.4 m circular segments in a flower petal pattern. At the University of Arizona we have developed a novel pupil slicer that will be used for ELT extreme adaptive optics (ExAO) on the up and coming ExAO instrument, GMagAO-X. This comes in the form of a six-sided reflective pyramid with a hole through the center known as a “hexpyramid”. By passing the GMT pupil onto this reflective optic, the six outer petals will be sent outward in six different directions while the central segment passes through the center. Each segment will travel to its own polarization independent flat fold mirror mounted on a piezoelectric piston/tip/tilt controller then onto its own commercial 3,000 actuator deformable mirror (DM) that will be employed for extreme wavefront control. This scheme of seven DMs working in parallel to produce a 21,000 actuator DM is a new ExAO architecture that we named a “parallel DM,” in which the hexpyramid is a key optical component. This significantly surpasses any current or near future actuator count for any monolithic DM architecture. The optical system is designed for high-quality wavefront (λ/10 surface PV) with no polarization errors and no vignetting. The design and fabrication of the invar mechanical mounting structure for this complex optical system is described in this paper.

Original languageEnglish (US)
Title of host publicationAdaptive Optics Systems VIII
EditorsLaura Schreiber, Dirk Schmidt, Elise Vernet
ISBN (Electronic)9781510653511
StatePublished - 2022
EventAdaptive Optics Systems VIII 2022 - Montreal, Canada
Duration: Jul 17 2022Jul 22 2022

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceAdaptive Optics Systems VIII 2022


  • adaptive optics
  • ELT
  • wavefront 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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