Laser-induced damage on ordered and amorphous sol-gel silica coatings

A sol-gel antireflective (AR) coating with an ordered structure has been studied recently for its promising application in high power laser system. However, it is not clear how good the coating is when compared with the traditional sol-gel ones. To address this issue, a comparative study of the laser-induced damage thresholds (LIDTs) of three sol-gel silica coatings was conducted with 1064 nm laser irradiation. Ordered mesoporous, amorphous porous and dense coatings were prepared with acid or base catalysts, and were compared in terms of the skeleton and pore structures, the absorptions, the LIDTs, the damage morphologies and so on. It was found that the former two coatings were comparably strong in resisting laser damage, and that high porosity was the most important factor affecting the LIDT. Besides, the ordered mesoporous coating with a fiber-like skeleton led to the minimum damage of the substrate in all the samples.