Phase mask for infrared lens athermalization - Design considerations

Shay Elmalem, Emanuel Marom

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


Design of Infra-red (IR) imaging systems requires solutions for overcoming thermal variations of IR lenses, in particular those fabricated out of Germanium. The known thermal dependence of the index of refraction of Germanium results in significant focal shift, which produces image blur. Known solutions to overcome the thermal fluctuations are reviewed. A solution based on an alloptical phase mask with no moving parts will be shown to provide improved imagery for broad band IR scenes in the presence of wide temperature variations. Phase mask design considerations and trade-offs are analyzed.

Original languageEnglish
Title of host publicationAdvanced Optics for Defense Applications
Subtitle of host publicationUV through LWIR
EditorsPeter L. Marasco, Bjorn F. Andresen, Jay N. Vizgaitis, Jasbinder S. Sanghera, Miguel P. Snyder
ISBN (Electronic)9781510600638
StatePublished - 2016
EventAdvanced Optics for Defense Applications: UV through LWIR - Baltimore, United States
Duration: 17 Apr 201619 Apr 2016

Publication series

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


ConferenceAdvanced Optics for Defense Applications: UV through LWIR
Country/TerritoryUnited States


  • Athermalization
  • Depth of field (DOF), phase mask
  • Infrared imaging


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