The dependence of defect formation in a high-purity synthetic SiO2 glass on F2 laser power was studied. Above the threshold value of ~10mJ/cm2pulse (~0.5MW/cm2), the concentration of the laser-induced E’ center created by the dissociation of Si-O-Si bond increased as a function of the F2 laser power squared. The quantum yield of the E’ center formed by the high-power F2 laser irradiation was some 3 orders of magnitude larger than that formed via 2-photon absorption processes of KrF or ArF laser pulses. This strongly suggested that irradiation with the high-power F2 laser created the E’ center via 2-step absorption processes.

Power Dependence of Defect Formation in SiO2 Glass by F2 Laser Irradiation. K.Kajihara, Y.Ikuta, M.Hirano, H.Hosono: Applied Physics Letters, 2002, 81[17], 3164-6