According with the set-up in Fig. 1, a BTAO coated sapphire
substrate was successfully bonded with an uncoated sapphire
substrate by the BTAO thin film after the above described laser
process. The substrates do not present any damage on the surface
and the irradiated area is recognizable through a whitish color in
contrast with the transparency of the non-irradiated area (not
shown). Fig. 4 shows an optical micrograph of one of the bonded
samples by focusing at the interface. The circular trajectory of the
laser beam (wobble) is recognizable at the beginning of the irradiated
lines, as well as the overlap of the lines, creating a fully
bonded area.