REFRACTIVE-INDEX CHANGE IN AL-ION-IMPLANTED SILICA GLASS()

Al+ ions have been implanted in silica glass at an acceleration energy of 200 eV and doses ranging from 1 x 10(13) to 1 x 10(17) ions cm(-2) . Infrared reflection spectra and ultraviolet, visible, and near-infra red absorption spectra have been measured. It was found that refractiv e index of silica glass increased by 6%-10% after implantation of 1 x 10(17) Al+ ions cm(-2). It was deduced that this refractive index chan ge is caused by the formation of Si-Si homobonds, but not by the decre ase in Si-O-Si bond angle which leads to compaction. (C) 1996 American Institute of Physics.