High-power laser systems require thin films with extremely low absorption. Ultra-low-absorption films are often fabricated via ion beam sputtering, which is costly and slow. This study analyzes the impact of doping titanium and annealing on the absorption characteristics of thin films, focusing on composition and structure. The results indicate that the primary factor influencing absorption is composition. Suppressing the presence of electrons or holes that do not form stable chemical bonds can significantly reduce absorption; for amorphous thin films, the structural influence on absorption is relatively minor. Thus, composition control is crucial for fabricating ultra-low-absorption films, while the deposition method is secondary. Ion beam-assisted electron-beam evaporation, which is relatively seldom used for fabricating low-absorption films, was employed to produce high-reflectivity films. After annealing, the absorption at 1064 nm reached 1.70 parts per million. This method offers a cost-effective and rapid approach for fabricating ultra-low-absorption films.

In this paper, the effect of an annealing treatment on the microstructure, mechanicalproperties and electrical conductivity of a deformed Cu-12.8 wt%Fe composite prepared bythe “casting/cold working” process is investigated. The Fe filaments exhibit the shapecharacteristic in the as-drawn composite as the annealing temperature is lower than 500°C. When the annealing temperature is above 500 °C, the Fe filaments undergo theinstability process in terms of boundary splitting, coarsening and breakup gradually. Thetensile strength gradually decreases with increasing annealing temperature due to thecoarsening of filament spacing. The work hardening for the composite annealed above 600 °Cis slower than that annealed at a lower temperature. The electrical conductivity reaches amaximum of 60%IACS at a temperature of 450 °C for one hour of annealing, and it furtherincreases with increasing annealing time at 450 °C to reach a plateau of 68% IACS. Thecurve between the tensile strength and electrical conductivity under different annealingprocesses indicates that the optimum annealing temperature for the Cu-Fe composite is 450°C.