Color-center formation in F-doped, OH-free synthetic SiO<sub>2</sub> glasses by irradiation with F<sub>2</sub> excimer lasers (157 nm) was examined as a function of the F content. The concentration of photoinduced E<sup>′</sup> centers was reduced to ~1/20 by 1 mol.% F <sub>2</sub> doping and remained almost constant on further doping to 7.3 mol. %. The absorption edge was considerably shifted to a lower wavelength (157.4 nm→153 nm for a 5-mm-thick sample) by 1-mol. % doping and decreased only slightly on further doping. The intensities of the Raman bands that are due to three- and four-membered ring structures were significantly reduced by 1-mol. % F doping. These results strongly suggest that elimination of strained Si—O—Si bonds by F doping plays a central role in the improvement of radiation resistance of SiO<sub>2</sub> glasses to F<sub>2</sub> laser light.
© 1999 Optical Society of America
(140.3330) Lasers and laser optics : Laser damage
(160.2750) Materials : Glass and other amorphous materials
(160.6030) Materials : Silica
(220.3740) Optical design and fabrication : Lithography
Hideo Hosono, Masafumi Mizuguchi, Linards Skuja, and Tohru Ogawa, "Fluorine-doped SiO2 glasses for F2 excimer laser optics: fluorine content and color-center formation," Opt. Lett. 24, 1549-1551 (1999)