Time-delayed source and interferometric measurement of domes and windows

William P. Kuhn, Matthew Dubin

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

2 Scopus citations


Measurement of the transmitted wavefront of domes and windows is a long-standing problem. One may use a large return sphere and measure the interference cavity without the dome present and again with the dome present. The difference between the two measurements is a double-pass measurement of the transmitted wavefront of the dome. Even so, the long coherence length of the source results in many extraneous fringe patterns. Windows may be tested by using a collimated source and return flat. A time-delayed source (TDS) having a short-coherence length is used to obtain a single interference pattern due only to interference of light reflected by the two surfaces of a dome or window. Standard phase shifting algorithms may be used with the TDS to measure the optical thickness of a dome or window without errors due to multiple reflections. Since most of the interferometer is common-path, environmental sensitivity is reduced and alignment is straightforward compared to typical interferometers. Finally, since there is no reference surface, stitching of sub-aperture measurements is simplified.

Original languageEnglish (US)
Title of host publicationWindow and Dome Technologies and Materials X
StatePublished - 2007
EventWindow and Dome Technologies and Materials X - Orlando, FL, United States
Duration: Apr 11 2007Apr 12 2007

Publication series

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


OtherWindow and Dome Technologies and Materials X
Country/TerritoryUnited States
CityOrlando, FL


  • Common path
  • Dome
  • Multiple reflections
  • Phase-shift
  • Short coherence
  • Stitching
  • Time-delay
  • Window

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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