Correlations between the refractive-index change and the concentration of an oxygen-deficient center (ODC) induced by thermal treatments and laser irradiation are examined to clarify the origin of laser-induced volume compaction in synthetic SiO<sub>2</sub> glasses. A linear correlation between them was clearly observed for thermally induced ODC, whereas no correlation was found for ArF or F<sub>2</sub> laser irradiation. The results demonstrate that the dominant origin of laser-induced compaction is not ODC formation. Furthermore, we found that the presence of H<sub>2</sub> in SiO<sub>2</sub> glass had no influence on volume compaction but enhanced crack formation upon laser irradiation, a phenomenon most likely due to stress corrosion.
© 2004 Optical Society of America
Yoshiaki Ikuta, Koichi Kajihara, Masahiro Hirano, and Hideo Hosono, "Correlation between Oxygen-Deficient Center Formation and Volume Compaction in Synthetic SiO2 Glass Upon ArF or F2 Excimer-Laser Irradiation," Appl. Opt. 43, 2332-2336 (2004)