Local atomic environment of Cu ions in ion-exchanged silicate glass waveguides: An x-ray absorption spectroscopy study

We present an x-ray absorption spectroscopy study at the Cu K edge on Cu-doped soda-lime and BK7 glass waveguides obtained by ion exchange under various preparation conditions. The total electron yield and x-ray fluorescence yield collection modes were used to evidence the chemical behavior of surfacial and deep Cu ions. In all the samples copper is found preferentially as Cu+ throughout the whole exchanged region. The first coordination shell is formed by two to three oxygen atoms at 1.86 Angstrom, much shorter than the Na-O bond (2.3 Angstrom) in soda-lime glasses. (C) 1997 American Institute of Physics.