Influence of impurities on laser-induced damage of sol-gel SiO2 films

Three kinds of anti-reflective SiO2 films, without impurities, with SiO2 particulate impurities and with CeO2 particulate impurities, were deposited on K9 glass by sol-gel dip-coating method. The influence of impurities on laser-induced damage of films was investigated before and after preconditioning with a 1 064 nm Nd:YAG pulsed laser. No obvious change in morphologies and damage threshold appears for pure films after conditioning. For the films with SiO2 impurities, 10 μm-size SiO2 particles show obvious micro-focusing effect and act as damage-initiating seeds, which can be removed by conditioning. Moreover, the samples with CeO2 impurities have intense absorbing character, and their laser-induced damage threshold is les