Patent ID: 7981824

Claim:
A quartz glass blank for an optical component for transmitting radiation of a wavelength of 15 nm and shorter, said blank being cylindrical and having a cylinder axis with a height, and comprising highly pure quartz glass, doped with titanium and/or fluorine, wherein said quartz glass has: a) micro-inhomogeneities caused by a local variance of a distribution of TiO 2 therein of less than 0.05% TiO 2 averaged over a volume element of (5 μm) 3 in relation to a mean value of a TiO 2 content in the quartz glass blank; b) a thermal expansion coefficient, averaged over the height of the cylinder axis, varying over an optically used surface of the quartz glass blank with a maximum inhomogeneity of less than 5 ppb/K; c) the thermal expansion coefficient varying along the optically used surface substantially according to Δα from the formula (1): Δ ⁢ ⁢ a = C 0 α + C 3 α ⁡ ( 2 ⁢ ( r R ) 2 - 1 ) + C 8 α ⁡ ( 6 ⁢ ( r R ) 4 - 6 ⁢ ( r R ) 2 + 1 ) ( 1 ) wherein a residual inhomogeneity of the thermal expansion coefficient after subtraction of Δα according to the formula (1) from the thermal expansion coefficient is not more than 0.5 ppb/K, where C 0 α <5 ppb/K; d) the thermal expansion coefficient having a radial variance over the optically used surface of the quartz glass blank of not more than 0.4 ppb/(K cm); and e) a stress birefringence at 633 nm averaged over the height of the cylinder axis of not greater than 2 nm/cm and not greater than a maximum stress birefringence (SDB) that varies over the optically used surface of the quartz glass blank substantially according to the formula (2): SDB = C 0 SDB + C 3 SDB ( 2 ⁢ ( r R ) 2 - 1 ) + C 8 SDB ⁡ ( 6 ⁢ ( r R ) 4 - 6 ⁢ ( r R ) 2 + 1 ) ( 2 ) where r is a radial distance from the cylinder axis; R is a maximum radius of the optically used surface; and C 0 , C 3 , C 8 are each an adaptation parameter of the associated spherical Zernike term of formulas 1 or 2.