Manufacturing of super-polished large aspheric/freeform optics

Dae Wook Kim, Chang Jin Oh, Andrew Lowman, Greg A. Smith, Maham Aftab, James H. Burge

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

14 Scopus citations

Abstract

Several next generation astronomical telescopes or large optical systems utilize aspheric/freeform optics for creating a segmented optical system. Multiple mirrors can be combined to form a larger optical surface or used as a single surface to avoid obscurations. In this paper, we demonstrate a specific case of the Daniel K. Inouye Solar Telescope (DKIST). This optic is a 4.2 m in diameter off-axis primary mirror using ZERODUR thin substrate, and has been successfully completed in the Optical Engineering and Fabrication Facility (OEFF) at the University of Arizona, in 2016. As the telescope looks at the brightest object in the sky, our own Sun, the primary mirror surface quality meets extreme specifications covering a wide range of spatial frequency errors. In manufacturing the DKIST mirror, metrology systems have been studied, developed and applied to measure low-to-mid-to-high spatial frequency surface shape information in the 4.2 m super-polished optical surface. In this paper, measurements from these systems are converted to Power Spectral Density (PSD) plots and combined in the spatial frequency domain. Results cover 5 orders of magnitude in spatial frequencies and meet or exceed specifications for this large aspheric mirror. Precision manufacturing of the super-polished DKIST mirror enables a new level of solar science.

Original languageEnglish (US)
Title of host publicationAdvances in Optical and Mechanical Technologies for Telescopes and Instrumentation II
EditorsRamon Navarro, James H. Burge
PublisherSPIE
ISBN (Electronic)9781510602038
DOIs
StatePublished - 2016
EventAdvances in Optical and Mechanical Technologies for Telescopes and Instrumentation II - Edinburgh, United Kingdom
Duration: Jun 26 2016Jul 1 2016

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume9912
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Other

OtherAdvances in Optical and Mechanical Technologies for Telescopes and Instrumentation II
CountryUnited Kingdom
CityEdinburgh
Period6/26/167/1/16

Keywords

  • Astronomical mirror
  • Freeform optics
  • Large optics
  • Optical fabrication
  • Optical metrology
  • Super-polished mirror

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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