Photoabsorption of Synthetic Silica Glass under ArF Excimer Laser Irradiation

• Published in: Japanese Journal of Applied Physics Vol. 40; no. 10R; pp. 5962 - 5965
• Main Authors: Shimbo, Masaru, Nakajima, Toshio, Tsuji, Naoki, Kakuno, Tsutomu, Obara, Takashi
• Format: Journal Article
• Language: English
• Published: 2001
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.40.5962

In-situ measurement of the transmittance change at 220 nm in synthetic silica glass under the ArF excimer laser irradiation showed three phenomenological stages: 1) initial coloring stage, 2) saturation stage where the coloring reaction equilibrates to the discoloring reaction and 3) heavy dosing stage where a rapid increase in photoabsorption occurs after an increase in the number of laser shots. The coloring rate at the initial stage depends only on the sum of the exposed laser power regardless of laser energy density, frequency and OH concentration. The concentration of OH in the glass reduces the photoabsorption at the saturation stage by increasing the extent of discoloring reaction while it scarcely influences on the number of shots at which the rapid photoabsorption occurs in the heavy-dose region.