Abstract
Properties of defects induced by irradiation with near-infrared femtosecond laser into a series of synthetic fused silicas of diverse OH contents are reported. Comparing with the sample before laser irradiation, two absorption bands centered around at 4.8 eV and 5.8 eV which correspond to E′ (≡Si•) center and non-bridging oxygen hole center (NBOHC, ≡Si-O•), respectively, were evidently observed after laser irradiation. A photoluminescence band with photon energy of 1.9 eV was observed in the samples bearing the two absorption bands. The intensity of photoluminescence relates to the OH contents and the irradiation depths under the surface of the samples. The mechanism for the 1.9 eV photoluminescence and generation of defects induced by ultrashort pulse laser were discussed.
