Fizeau interferometer with spherical reference and CGH correction for measuring large convex aspheres

M. B. Dubin, P. Su, James H. Burge

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

24 Scopus citations


Large, convex surfaces, such as secondary mirrors, have presented challenging metrology problems for many years. Over the years, new metrology approaches have been developed to keep pace with the ever changing definition of "large". The latest class of large secondary mirrors requires a new approach that is practical, scalable and can produce low uncertainty measurements. This paper presents a new configuration that uses a computer generated hologram based Fizeau interferometer to make sub-aperture measurements on large secondary mirrors. One of the key features of this system is that all of the surfaces used in the interferometer are spherical. Another key element is the ability to perform simultaneous phase shift interferometry which reduces sensitivity to vibration. An example system that is capable of measuring the Large Synoptic Survey Telescope secondary mirror is presented along with a sensitivity analysis.

Original languageEnglish (US)
Title of host publicationOptical Manufacturing and Testing VIII
StatePublished - 2009
EventOptical Manufacturing and Testing VIII - San Diego, CA, United States
Duration: Aug 4 2009Aug 5 2009

Publication series

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


OtherOptical Manufacturing and Testing VIII
Country/TerritoryUnited States
CitySan Diego, CA


  • Aspheres
  • Computer generated holograms
  • Interferometry
  • Optical testing

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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