Patent ID: 7312170

Claim:
An optical synthetic quartz glass article comprising a member that is made of synthetic quartz glass obtained by flame hydrolysis using a silicon compound as a raw material, said quartz glass having: a content A of SiOH that exceeds 10 wt ppm but that is not more than 400 wt ppm, a content B of fluorine in a range of 30 to 1000 wt ppm, hydrogen in a range of 0.1×10 17 to 10×10 17 molecules/cm 3 , a fictive temperature in a range of 1073 K to 1323 K; and wherein the total of A and B is 100 wt ppm or higher and the ratio of B/A has a value in a range of 0.25 to 25; wherein irradiating said member with 1×10 10 pulses or more of ArF excimer laser radiation at an energy density per pulse of 0.3 mJ/cm 2 yields a change in transmission wave plane per 1 cm thickness that is in a range of −0.5 to +0.5 nm for a radiation of 632.8 nm; and wherein irradiating said member with 1×10 7 pulses or more of ArF excimer laser radiation at an energy density per pulse of 10 mJ/cm 2 yields a change in transmission wave plane per 1 cm thickness that is in a range of 0 to +5 nm for a radiation of 632.8 nm.