Laser-induced damage of sol-gel silica acid and basic thin films

The sol-gel monolayer silica acid and basic thin films on K9 glass substrates were prepared with the dip method from acid and basic catalyzed silica sols, respectively. Both films have nearly similar optical thickness. The laser-induced damage thresholds(LIDT) of the two kinds of films were measured. Thermal absorption, porous ratio and surface morphologies of films were investigated by Stanford photo-thermal solutions, ellipsometer, atomic force microscope(AFM) and scanning electron microscope(SEM), respectively. Optical microscope was used to characterize the defects and impurities of films before laser irradiation and damage morphology after laser irradiation. The experimental results showed that compared with basic film, the silica acid film had larger absorption, smaller porous ratio