Optomechanical design considerations for a vacuum window for optical and infrared interferometry

F. Ernesto Penado, James H. Clark

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

1 Scopus citations


We present the results of analysis of a 6 in. diameter vacuum window. The design prevents contact between the metallic mounting cell and the glass window material, which can be a source of failure in the glass. The window transmits optical and infrared wavelengths for multi-baseline interferometry at the Navy Precision Optical Interferometer (NPOI). Our analysis investigates possible interactive contact with the mounting cell and consequent failure of the window. Our design philosophy is to avoid overconstraining the glass window and maintain integrity of the vacuum seal through diurnal and seasonal temperature changes. The objective is to create no additional crack nucleation sites or initiate cracking in the brittle material due to the mount design. The window is unconstrained laterally and free to expand radially. Furthermore, the glass is free to expand in the thickness direction over the expected temperature range. The lack of contact due to thermal expansion over a broad temperature range and bending stresses due to loading were calculated to ensure the integrity of the assembly. In this paper, we describe our design approach, method of analysis, results, and recommendations. Our analysis shows that a simply supported window can be designed to achieve no metal to glass contact.

Original languageEnglish (US)
Title of host publicationOptomechanical Engineering 2019
EditorsKeith B. Doyle, Jonathan D. Ellis
ISBN (Electronic)9781510628939
StatePublished - 2019
EventOptomechanical Engineering 2019 - San Diego, United States
Duration: Aug 14 2019 → …

Publication series

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


ConferenceOptomechanical Engineering 2019
Country/TerritoryUnited States
CitySan Diego
Period8/14/19 → …


  • NPOI
  • Navy Precision Optical Interferometer
  • Optical interferometry
  • Optomechanics
  • Plate analysis
  • Vacuum 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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