Influence of substoichiometer on the laser-induced damage characters of HfO2 thin films

Abstract: HfO2 is one of the most important high refractive index materials for depositing high power optical mirrors. In this research, HfO2 thin films were prepared by dual-ion beam reactive sputtering method, and the laser-induced damage thresholds (LIDT) of the sample were measured in 1-on-1 mode for laser with 1064nm wavelength. The results indicate that the LIDT of the as-grown sample is only 3.96J/cm2, but it is increased to 8.98J/cm2 after annealing under temperature of 200°C in atmosphere. By measuring the laser weak absorption and SIMS of the samples, we deduced that substoichiometer is the main reason for the low LIDT of the as-grown sample, and the experiment results were well explained with the theory of electronic-avalanche ionization. [Copyright &y& Elsevier]