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Proceedings Paper

Designing apochromatic telescope objectives with liquid lenses
Author(s): Robert D. Sigler
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Paper Abstract

The traditional approach to designing a high-performance, apochromatic, telescope objective has always required the incorporation of an abnormal dispersion glass or crystal. These materials are notorious for their high cost and poor mechanical properties. Recently, some optical liquids have been found that have dispersion properties unequaled by any known glass or crystal. This has opened the way to lower-cost apochromatic objectives. While many of the problems associated with the use of traditional abnormal dispersion materials can be avoided, the incorporation of an abnormal dispersion liquid 'element' in combination with common (normal dispersion) glasses in a telescope objective design creates some unique design considerations. In this paper, a comparison of the dispersion characteristics of glasses and liquids are presented. Also presented are specific design examples that illustrate the performance improvements possible with glass-liquid combinations. The problems associated with obtaining high precision refractive index measurements on liquids and a comparison of liquid catalog and measured indices are discussed. Finally, some design issues unique to liquid lenses such as athermalization, sealing, volumetric expansion accommodation, freezing, and long-term stability are addressed.

Paper Details

Date Published: 1 November 1991
PDF: 24 pages
Proc. SPIE 1535, Passive Materials for Optical Elements, (1 November 1991); doi: 10.1117/12.48306
Show Author Affiliations
Robert D. Sigler, Lockheed Missiles & Space Co., Inc. (United States)

Published in SPIE Proceedings Vol. 1535:
Passive Materials for Optical Elements
Gary W. Wilkerson, Editor(s)

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