Abstract

An interferometric method has been developed to determine the linear coefficient of thermal expansion of optical materials that are available only in short sample lengths (1.5 cm or less). The method utilizes the simple fringe pattern resulting from a thin air wedge formed between two fused-quartz (fused-silica) optical flats; the top flat is supported by the sample by means of a fused-quartz screw. The expansion of the material is determined by relating its change of length to the measured change of fringe spacing, as temperature is changed. Three different techniques for controlling the temperature of the sample are discussed. Measurements have been made in the temperature range 0°–90°C for various optical materials: single crystals, polycrystals, and glasses.

© 1968 Optical Society of America

Precision Thermal Expansion Measurements on Low Expansion Optical Materials

W. A. Plummer and H. E. Hagy
Appl. Opt. 7(5) 825-831 (1968)

Low Temperature Thermal Expansion Measurements on Optical Materials

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Interferometric method for concurrent measurement of thermo-optic and thermal expansion coefficients

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Apparatus for Measuring the Thermal Expansion of Optical Materials from 30°C to 250°C

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Simultaneous interferometric measurement of linear coefficient of thermal expansion and temperature-dependent refractive index coefficient of optical materials

James A. Corsetti, William E. Green, Jonathan D. Ellis, Greg R. Schmidt, and Duncan T. Moore
Appl. Opt. 55(29) 8145-8152 (2016)