Jacobs S F, Johnston S C, Sasian J M, Watson M, Targove J D, Bass D
Appl Opt. 1987 Oct 15;26(20):4438-42. doi: 10.1364/AO.26.004438.
How does thermal cycling hysteresis affect surface figure in low expansivity mirror substrates? Zerodur, ULE, and Cer-Vit 20.3-cm (8-in.) diam mirrors and dilatometer samples were thermally cycled at 6 and 60 K/h with uniform and nonuniform heating. Figure distortions as large as lambda/10 were observed only with nonuniform heating of standard Zerodur, which was the only material exhibiting thermal hysteresis. A new experimental Zerodur appears to be free of this problem.
