Shear test of the off-axis surface with an axis-symmetric parent

Peng Su, James H. Burge, Jose Sasian

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

2 Scopus citations


Interferometers with additional test optics are frequently used for measuring aspherical optical surfaces. In optical testing it is desirable to separate the figure measurement errors due to the test surface from figure errors that arise in the test equipment. For axially symmetric optics this is accomplished by rotating the surface being measured with respect to the test system. The data can then be processed to separate the non-axially symmetric errors that are fixed in the test system and those that rotate with the part. The axially symmetric errors cannot be distinguished with this technique. In this paper we present a variation of this technique for off-axis aspheric optics. The rotation is performed by rotating the test surface about the optical axis of its parent asphere, which may be outside the physical boundary of the test surface. As these rotations cannot be large, this motion is better described as a shear of the optical surface with respect to the test optics. By taking multiple measurements with different amounts of rotational shear and using maximum likelihood estimation methods, one can separate the errors in the test optics from the irregularity in the optical surface.

Original languageEnglish (US)
Title of host publicationOptical Manufacturing and Testing VII
StatePublished - 2007
EventOptical Manufacturing and Testing VII - San Diego, CA, United States
Duration: Aug 28 2007Aug 29 2007

Publication series

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


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


  • Aspheres
  • Interferometry
  • Optical fabrication
  • Optical testing
  • Telescopes

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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