The influence of co-doping agents on bismuth clustering in silica synthesized by SPCVD

Abstract

We investigated the variation of near-infrared (NIR) luminescence spectra of bismuth-doped silica-based glasses caused by exposure to intense deep UV (193 nm wavelength) laser radiation. Bismuth-doped optical waveguides consisting of silica with additives of Al and P as the light-guiding core, synthesized via surface-plasma chemical vapour deposition (SPCVD) technology, served as the samples in our experiments. Spectra of steady-state NIR luminescence excited by 808, 904, and 970 nm wavelength laser diodes were measured in a wavelength band of 1-2 μm at temperatures of 105 and 300 K. We found that exposing the glass to intense ArF excimer laser radiation leads to NIR luminescence integral intensity and spectrum profile changes. The observed changes are discussed in the assumption that the UV laser exposure causes photoinduced rearrangement of the glass network in the vicinity of bismuth inclusions. It is expected that the latter are present in the glass network in the nature of separate ions, atoms, as well as 3D clusters.