Power dependence of defect formation in SiO2 glass by F2 laser irradiation

The dependence of defect formation in a high-purity synthetic SiO2 glass on F-2 laser power was studied. Above the threshold value of similar to10 mJ cm(-2) pulse(-1) (similar to0.5 MW cm(-2)), the concentration of the laser-induced E-' center created by the dissociation of Si-O-Si bond increased as a function of the F-2 laser power squared. The quantum yield of the E-' center formed by the high-power F-2 laser irradiation was similar to3 orders of magnitude larger than that formed via two-photon absorption processes of KrF or ArF laser pulses. This strongly suggests that irradiating with the high-power F-2 laser creates the E-' center via two-step absorption processes. (C) 2002 American Institute of Physics.