Preparation of high laser-induced damage threshold Ta2O5 films

High laser-induced damage threshold (LIDT) Ta2O5 films were prepared by the sol-gel method using TaCl5 as a new precursor. The optical properties, surface morphologies, chemical composition, absorption and LIDT of the films were investigated. The results showed that the transparent and homogenous Ta2O5 films had small surface roughness, low absorption and high LIDT even with large number of layers. The maximum LIDT at 1064 nm and 12 ns of the films was 24.8 J/cm2. The ion chromatograph and Fourier transform infrared spectrum were used to reveal the functions of the addition of H2O2 in the sol formation. It was shown that H2O2 had two important functions, which were the decrease of Cl element content and the rapid generation of tantalum oxide. The high LIDT achieved was mainly due to the nearly free of defects in the films.