Optically induced defects in vitreous silica

We report the observation of photoluminescence (PL) in optically damaged vi treous silica (v-SiO2) and its gradual decrease by annealing at temperature range from room temperature to 773 K. Optical damage was induced by tightl y focused picosecond or femtosecond irradiation inside v-SiO2. FL bands at 280, 470 and 650 nm were observed. The PL can be excited by 250 nm irradiat ion, which corresponds to the absorption band of the oxygen vacancy, V-O. T he decrease of PL with annealing is explained by structural modifications o f the defects in the damaged area. (C) 2000 Elsevier Science B.V. All right s reserved.