In a synthetic quartz glass ingot which is produced by vapor phase
hydrolyzing or oxidatively decomposing a silica-forming starting compound
in an oxyhydrogen flame such that silica growth in a direction occurs at
a silica particle deposition and melting face, striae visible when viewed
from a direction perpendicular to the silica growth direction are
distributed periodically over the silica growth direction. The ingot can
be used in the production of optical-grade high-homogeneity synthetic
quartz glass elements for excimer laser applications, particularly ArF
excimer laser applications, in the production of laser damage-resistant
optical elements used with light sources such as excimer lasers, and in
the production of UV optical fiber.