Surface modification of SiO2 glass by laser processing

Various oxide films on SiO₂ glass substrates were irradiated by a laser beam. A continuous CO₂ laser source (wavelength 10.6 μm) was used for this purpose; the composition change at the surface layer was determined by Rutherford backscattering spectrometry (RBS). All the alkaline-earth oxides as well as those of lanthanum and yttrium, entered the glass after treatment. ZrO₂ and CeO₂, however, did not enter the SiO₂ glass due to laser irradiation. It is interesting, however, that a film of ZrO₂ + Al₂O mixture easily entered into the SiO₂ glass by laser processing. The conditions and mechanism of laser-enhanced interaction of ZrO₂ or other oxide films with SiO₂ glass surfaces are discussed especially in view of their structural behaviour in glass.