Temperature dependence of the extinction coefficient of fused silica for CO(2) laser wavelengths.

The mechanism of the interaction of CO(2) laser radiation with fused silica is determined by the absorption depth of the radiation in the material. The extinction coefficient of a number of high-purity fused silica samples has been measured by the transmission method by fabricating samples approximately 30 microm in thickness. Results obtained agree with the latest reported values. In addition, samples were heated by an auxiliary CO(2)laser and the extinction coefficient determined as a function of temperature for six CO(2) laser lines. No significant difference in the extinction coefficient was observed for samples from different makers of the high-purity silica. Measurements were also conducted on a silica-rich glass Vycor and a significant difference was observed.