Abstract: Disclosed are high purity synthetic silica glass material having a high OH concentration homogeneity in a plane perpendicular to the optical axis, and process of making the same. The glass has high refractive index homogeneity. The glass can have high internal transmission of at least 99.65%/cm at 193 nm. The process does not require a post-sintering homogenization step. The controlling factors for high compositional homogeneity, thus high refractive index homogeneity, include high initial local soot density uniformity in the soot preform and slow sintering, notably isothermal treatment during consolidation.

Abstract: Titania-containing silica glass bodies and extreme ultraviolet elements having low levels of striae are disclosed. Methods and apparatus for manufacturing and measuring striae in glass elements and extreme ultraviolet elements are also disclosed.

Abstract: These glass bodies are light weight porous structures such as a boules of high purity fused silica (HPFS). More specifically, the porous structures are supports for HPFS mirror blanks. Porous glass is made utilizing flame deposition of pure silica or doped silica in a manner similar to the production of high purity fused silica. Bubbles or seeds are formed in the glass during laydown. Finely divided silicon carbide (SiC) particles are used to form the bubbles. At least one layer of porous glass is formed in the boule.

Abstract: Fused silica articles exhibiting improved internal transmission and decreased absorption change when irradiated with a laser when compared with fused silica articles containing lower levels of aluminum. The articles also exhibit induced transmission when irradiated with a laser. The articles also exhibit improved off-axis refractive index homogeneity.

Abstract: Fused silica members having high internal transmission and low birefringence are disclosed. Methods of making such fused silica members are also disclosed. According to the present invention, fused silica members having an internal transmission equal to or greater than 99.65%/cm at 193 nm and having an absolute maximum birefringence along the use axis of less than or equal to 0.75 nm/cm are provided.

Abstract: Titania-containing silica glass bodies and extreme ultraviolet elements having low levels of striae are disclosed. Methods and apparatus for manufacturing and measuring striae in glass elements and extreme ultraviolet elements are also disclosed.

Abstract: Fused silica articles exhibiting improved internal transmission and decreased absorption change when irradiated with a laser when compared with fused silica articles containing lower levels of aluminum. The articles also exhibit induced transmission when irradiated with a laser. The articles also exhibit improved off-axis refractive index homogeneity.

Abstract: Fused silica members having high internal transmission and low birefringence are disclosed. Methods of making such fused silica members are also disclosed. According to the present invention, fused silica members having an internal transmission equal to or greater than 99.65%/cm at 193 nm and having an absolute maximum birefringence along the use axis of less than or equal to 0.75 nm/cm are provided.

Abstract: A furnace for the deposition and collection of molten silica particles to form a solid body, the furnace comprising a collection vessel, the base of which is lined with a purified refractory material, and a method of forming the solid body which comprises lining the base of the collection cup with crushed particles of purified refractory material.

Abstract: A method of producing, by flame hydrolysis, a fused silica glass containing titania which comprises delivering a mixture of a silica precursor and a titania precursor in vapor form to a flame, passing the vapor mixture through the flame to form SiO.sub.2 --TiO.sub.2 particles, and depositing the particles within a furnace where they melt to form a solid glass body.

Abstract: Fused silica boules (19) having improved homogeneity are produced by causing the boule (19) to flow radially during its formation to achieve local mixing between portions of the boule which may have experienced different laydown conditions. The mixing is achieved by one or a combination of: (1) use of a containment vessel (13) having a gently sloping containment wall (22); (2) use of a containment vessel (13) whose inner radius (r.sub.v) is substantially larger than the outermost radius (r.sub.b) of the burners (14) used to produce the boule (19); and/or (3) maintaining the boule (19) at a sufficiently high temperature during laydown so that radial flow is achieved with a minimum head height of glass. Large blanks having high homogeneity can be made from such boules, e.g., blanks having diameters above 200 millimeters and .DELTA.n values of less than 0.25.times.10.sup.-6.

Abstract: Oscillation/rotation patterns for improving the off-axis homogeneity of fused silica boules are provided. The patterns reduce the optical effects of periodic off-axis striae by decreasing the ratio of .DELTA.n.sub.striae to .DELTA.z.sub.striae, where .DELTA.n.sub.striae is the average peak-to-valley magnitude of the striae and .DELTA.z.sub.striae is their average peak-to-peak period. The oscillation/rotation patterns have long repeat periods and cause soot-producing burners to trace out substantially spiral-shaped patterns on the surface of the boule.

Abstract: Titania-containing silica glass bodies and extreme ultraviolet elements having low levels of striae are disclosed. Methods and apparatus for manufacturing and measuring striae in glass elements and extreme ultraviolet elements are also disclosed.