Published online by Cambridge University Press: 21 February 2011
photoluminescence in the visible range in high purity silica rods at room temperature was studied using 6.4 eV photons as the excitation source. Electron spin resonance (ESR) was used to monitor the induced paramagnetic centers. Broad luminescence bands at 2.7 eV, 2.2 eV and 1.9 eV were observed. The relative intensities of these bands were found to be intensity dependent. The fluence dependence of these bands were also studied. The results are discussed in relationship to the excitonic mechanism for defect generation in silica.