A novel technique for doping silicate glasses with transition metals for waveguides applications

S. Ali^a,*, F. Gonella^b, E. Cattaruzza^b

a. INFM - Universita di Padova, via Marzolo, 8, Padova 35131, Italy

b. Physical Chemistry Deptt., Università Ca' Foscari, Dorsoduro 2137, Venezia I-30123, Italy

Abstract

Field-Assisted Solid-State Ion-Exchange (FASSIE) technique for doping silicate glasses with transition metals has been attracting much attention for its potential applications in light waveguides, luminescent materials and for the possibility to realize systems in which formation of metal nanoclusters is controlled by suitable post-exchange techniques. In this work, metallic films of either silver or gold are deposited onto the soda-lime and borosilicate glasses by the magnetron rf-sputtering technique. Due to an external applied electric field, metal ions diffuse into the glass by replacing its alkali content at different values of temperature and electric field. The nanocomposites are then characterized by secondary ion mass and m-line spectrometries, optical absorption and transmission electron microscopy, indicating that the migration not only depends on the experimental conditions but also on the local matrix and the chemical phenomena occurring at the metal/glass interface. In the case of both transition metals, dark lines presence suggests that the samples may actually support guided modes, although the quality of the surface creates some problems for the prism coupling used in the measurements. In particular, the yet broaden dips seem to indicate two modes in the visible and one in the IR, as expected for a waveguide, in which the number of supported modes decreases as the light wavelength increases.