Non-linear glasses by metal cluster formation: synthesis and properties

Abstract

Light waveguides were obtained by Na + + ion-exchange in a commercial soda-lime glass of composition (wt%): 71.9 SiO 2, 1.9 Al 2O 3, 6.8 CaO, 1.1 K 2O, 4.4 MgO, 13.5 Na 2O, 0.4 SO 3, with small contaminations of iron (15 ppm) and arsenic (300 ppm). Glass samples were immersed for 30 min in a molten salt bath of molar concentration 0.1 % AgNO 3 in NaNO 3 at 320 °C. Ion-exchanged samples were irradiated with helium, lithium and neon ions at an energy of 100 keV, with fluences in the 1×10 16–1×10 17 ions/cm 2 range and current densities between 1 and 8 μA/cm 2. The effect of the substrate temperature (room temperature, 90, 150 and 250 °C) was investigated. The formation of nanometer-size silver precipitates was observed, after irradiation, depending on the treatment conditions. The results were interpreted on the basis of the diffusivity of silver at the different temperatures and of the values of the energy deposited by the ion beams in electronic (ionization) processes and elastic collisions. Preliminary measurements of the third-order contribution to the electrical susceptibility indicate that the obtained materials exhibit optical non-linear properties which are interesting for the fabrication of optoelectronic devices.