| ULE® The zero expansion titania-silica binary glass ULETM offers an optimum combination of thermal, mechanical, and optical properties which make it an ideal material for precision optical structures and lightweight telescope mirrors. Its near-zero thermal expansion over the ambient operating temperature range helps preserve optical figure; the absence of hysteresis in its thermal expansion curve ensures dimensional stability of the mirror in extreme environments; its low density affords high specific stiffness thereby reducing elastic deformation of lightweight structures; its high fatigue resistance permits higher long-term stress without compromising mechanical reliability; and its excellent optical and birefringence properties facilitate inspection and quality assurance in terms of thermal expansion homogeneity, defect level, and residual strain. |
