Periodical gratings in mixed-oxide films by laser-interference irradiation

The synthesis of mixed titania-silica oxide thin films by a sol-gel process and the direct two-dimensional (2D) microstructuring of these films by irradiation was analyzed using nanosecond-laser-pulse interference patterns. The strong absorption of light by the Ti50Si50 film below 350 nm, evaluated by recording UV-vis spectra, indicates the high interaction of the sol-gel material with the laser radiation at 266 nm. The structure depth and the homogeneity of the structured surfaces was studied as a function of the laser fluence and the number of laser pulses. The results show that because of the high energy at the interference maxima it is possible to form crystalline-oxide phases in the otherwise amorphous mixed oxide.