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In this study, four Ta 2 O 5 -based mixture coatings, including Ta 2 O 5 -TiO 2 , Ta 2 O 5 -HfO 2 , Ta 2 O 5 -Al 2 O 3 , and Ta 2 O 5 -SiO 2 , are deposited via plasma-ion-assisted electron-beam co-evaporation and compared with a Ta 2 O 5 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 Ta 2 O 5 -HfO 2 mixture coating exhibits a larger optical bandgap and higher femtosecond LIDT than other coatings. The 1-on-1 LIDT of the Ta 2 O 5 -HfO 2 mixture coating is approximately 1032.3 mJ/cm2 (170 fs), which is 25% higher than that of the Ta 2 O 5 monolayer coating. We believe the Ta 2 O 5 -HfO 2 mixture will be useful for various multilayer coatings such as chirped mirrors and other mirrors in femtosecond laser applications. • The effect of doping materials on Ta 2 O 5 -X mixtures is systematically studied. • Ta 2 O 5 -X mixtures with similar refractive indices show different optical bandgaps. • The optical bandgap affects the femtosecond laser-induced damage threshold. • The Ta 2 O 5 –HfO 2 mixture coating exhibits excellent performance. [ABSTRACT FROM AUTHOR]

HfO 2 monolayer coatings are grown by plasma-enhanced atomic layer deposition (PEALD), and the effects of the thermal annealing atmosphere and temperature on the surface morphology, crystal structure, chemical composition, optical absorption, and laser-induced damage threshold (LIDT) of the HfO 2 monolayer coatings are investigated. The experimental results show that annealing in an oxygen atmosphere is more beneficial to the decomposition of impurity compounds (carbonates and amines) and the elimination of oxygen deficiency in HfO 2 coating than in a nitrogen atmosphere. Compared to the as-deposited coating, the HfO 2 coating annealed under an oxygen atmosphere and specific temperature has lower C and N impurity contents, a better stoichiometric ratio, and thus lower absorption and higher LIDT. The highest LIDT (at 355 nm) of 6.3 J/cm2 is obtained at an annealing temperature of 700 ℃, which is approximately three times that of the as-deposited coating. We believe that this experimental result can help improve the LIDT of PEALD-grown oxide coatings or other oxide coatings containing similar impurities. • The effect of annealing on the properties of PEALD HfO 2 coatings is investigated. • The carbonates and amines in the HfO 2 coating decompose during annealing. • The oxygen-annealed HfO 2 coating has lower absorption and higher LIDT. • The oxygen-annealed HfO 2 coating shows different damage morphology. [ABSTRACT FROM AUTHOR]