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Negative thermal expansion ALLVAR alloys for athermalization (Conference Presentation)
Author(s): James A. Monroe; Jeremy S. McAllister; Jay Zgarba; David Squires; John P. Deegan

Paper Abstract

Temperature changes can detrimentally affect an optic’s performance due to changes in radius of curvature, thickness, and index of refraction. This is a particularly tricky problem when combinations of these changes produce a decrease in focus with increasing temperature such as infrared systems. Current solutions include active focusing mechanisms and nesting tubes of different materials that cancel each other’s thermal expansion, but these solutions add size and mass. ALLVAR alloys are the only metals that shrink when heated and expand when cooled, known as negative thermal expansion (NTE), making them a unique solution to this thermal focus shift problem. They can exhibit NTE down to -30 ppm/K. This unique property opens the opto-mechanical design window for athermalized optics with decreased size and weight. This presentation will discuss the optic design potential of ALLVAR alloys and exhibit the first optic demonstration of ALLVAR in a visible and infrared optic assembly.

Paper Details

Date Published: 18 November 2019
PDF
Proc. SPIE 11175, Optifab 2019, 111750R (18 November 2019); doi: 10.1117/12.2536862
Show Author Affiliations
James A. Monroe, ALLVAR (United States)
Jeremy S. McAllister, ALLVAR (United States)
Jay Zgarba, ALLVAR (United States)
David Squires, ALLVAR (United States)
John P. Deegan, Rochester Precision Optics, LLC (United States)


Published in SPIE Proceedings Vol. 11175:
Optifab 2019
Blair L. Unger; Jessica DeGroote Nelson, Editor(s)

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