Formation and photobleaching of 5 eV bands in ion-implanted SiO2:Ge and SiO2glasses for photosensitive materials

Formation and photobleaching of optical absorption bands in the 5 eV region were examined in proton-implanted 5GeO-95SiO 2 glasses and SiO 2 glasses implanted with Si, Ge, B or P ions. A conspicuous increase in the intensity of the 5 eV band, which is attributed to oxygen vacancies, was seen in both substrates after implantation. However, a distinct difference was observed in bleaching with 5 eV light between the H-implanted SiO 2 :Ge glasses and the implanted SiO 2 glasses. In the former the 5 eV band was bleached and intense absorptions above 5 eV emerged, whereas in the latter bleaching occurred in the whole UV region. This distinct bleaching nature provides implanted glasses with the possibility of modification of the refractive index by UV illumination.