Fabrication of a Composite Film Optic with High Transmittance in Vis and IR Regions for an Optical System

In this study, a lightweight composite polyimide film optic with antireflective coating was prepared using an ion-beam-assisted reactive sputtering method. It exhibited high transmittance in visible (87%, 0.5 similar to 0.8 mu m), short (86%, 1.8 similar to 2.7 mu m) and middle (78%, 3.3 similar to 5.4 mu m) wavelength infrared regions. Additionally, it also showed great optical homogeneity (0.006 lambda in RMS and 0.034 lambda in PV, lambda = 632.8 nm) with smooth surfaces (RMS = 0.786 nm). The thermal stability of the polyimide film was also effectively maintained after the antireflective coating. At the same time, by utilizing the hydrophobic properties of coating materials (Ta2O5/SiO2), the antireflective layer acted as an effective water barrier on the film surface to reduce the water absorption.