Optical and femtosecond laser-induced damage-related properties of Ta2O5-based oxide mixtures

Abstract

In this study, four Ta2O5-based mixture coatings, including Ta2O5-TiO2, Ta2O5-HfO2, Ta2O5-Al2O3, and Ta2O5-SiO2, are deposited via plasma-ion-assisted electron-beam co-evaporation and compared with a Ta2O5 monolayer coating. The chemical compositions, microstructures, and optical and femtosecond laser-induced damage threshold (LIDT) properties of the coatings are investigated. For different doping materials, when the refractive indices of the mixture coatings are close, the femtosecond LIDTs exhibit a considerable difference. The experimental results indicate that the Ta2O5-HfO2 mixture coating exhibits a larger optical bandgap and higher femtosecond LIDT than other coatings. The 1-on-1 LIDT of the Ta2O5-HfO2 mixture coating is approximately 1032.3 mJ/cm2 (170 fs), which is 25% higher than that of the Ta2O5 monolayer coating. We believe the Ta2O5-HfO2 mixture will be useful for various multilayer coatings such as chirped mirrors and other mirrors in femtosecond laser applications.