High Power Laser Science and Engineering, Volume. , Issue , ()
Fabrication of Ultra-Low Absorption Thin Films via Ion Beam Assisted Electron Beam Evaporation [Early Posting]
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. By 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 ppm. This method offers a cost-effective and rapid approach for fabricating ultra-low absorption films.