QUARTZ GLASS BLANK AND METHOD FOR PRODUCING SAID BLANK

摘要

The invention relates to a quartz glass blank for an optical component for transmitting radiation with a wavelength of 15 nm and shorter. Said blank consists of a highly pure quartz glass, doped with titanium and/or fluorine, which is characterised by an extremely high degree of homogeneity. The homogeneity relates to the following characteristics: a) micro-inhomogeneities caused by a local variance of the TiO2 distribution (< 0.05 % TIO2, averaged over a volume element of (5µm)<3> in relation to the mean value of the TiO2 content), b) an absolute, maximum inhomogeneity in the thermal expansion coefficient Deltaalpha in the main functional direction (< 5 ppb/K), c) a radial variance of the thermal expansion coefficient over the usable surface of the quartz glass blank by a maximum 0.4 ppb / (K'cm); d) a maximum stress birefringence at 633 nm in the main functional direction of 2nm/cm, with a specific progression and e) a specific progression of the Deltaalpha, averaged according to (b) on the optical surface. Said quartz glass blank can only be obtained from a large volume rod-type starting body consisting of doped quartz glass that has been produced by the flame hydrolysis of a compound containing silicon, titanium and/or fluorine, said starting body being formed into a homogeneous quartz glass blank using several forming and homogenising steps.