Abstract

A simple interferometric test setup for measuring thermal expansion coefficients as low as 1 × 10⁻⁸/°C is described. The sample to be tested is polished optically flat, interference fringes are formed between the front surface of the sample and a reference surface, and their movement, as boiling water is applied to the back side of the test piece, is observed. When this process was applied to Zerodur, approximate agreement with expected values was achieved. A small permanent change in the Zerodur optical figure occurred as a result of this test procedure, suggesting that Zerodur should not be exposed to strong thermal shock during use.

© 1984 Optical Society of America

Thermal expansion uniformity of materials for large telescope mirrors

Stephen F. Jacobs, Dean Shough, and Cliff Connors
Appl. Opt. 23(23) 4237-4244 (1984)

Thermal Expansion of Borosilicate Glass, Zerodur, Zerodur M, and Uncer amized Zerodur at Low Temperatures

J.H. Burge, T. Peper, and S.F. Jacobs
Appl. Opt. 38(34) 7161-7162 (1999)

Thermal expansion and length stability of Zerodur in dependence on temperature and time

Otto Lindig and Wolfgang Pannhorst
Appl. Opt. 24(20) 3330-3334 (1985)

Ultraprecise thermal expansion measurements of seven low expansion materials

J. W. Berthold and S. F. Jacobs
Appl. Opt. 15(10) 2344-2347 (1976)

Expansion hysteresis upon thermal cycling of Zerodur

Stephen F. Jacobs, Steve C. Johnston, and Glenn A. Hansen
Appl. Opt. 23(17) 3014-3016 (1984)