Coloring effects of optical antireflective film irradiated by 60 keV protons

In this study, the irradiation coloring effects by 60 keV protons on space applied lens coated with a MgF2/ZrO2/Al2O3 optical multilayer antireflection film were investigated by ground experiment and computer simulation methods. The energy loss within each layer of the antireflection film caused by proton irradiation was calculated using SRIM program based on the Monte Carlo simulation approach. It was shown that the lower energy proton irradiation led to a smaller range, but induced larger energy loss, resulting in worse damage in the antireflection film. Degradation in spectrum transmission of the lens irradiated by 60 keV protons using a synthesized space irradiation simulation facility was examined. Evolutions of the color centers in the irradiated films were also evaluated by absorption spectrometry techniques. It was found that the F2 color centers in the MgF2 film, and the VŌH and F2+ color centers in the Al2O3 film are responsible for the absorption bands at 370 nm, 400 nm and 440–450 nm, respectively. The absorption band at 490 nm was caused by F+ color centers in the ZrO2 film, and the absorption band at 580–660 nm was induced by some impurity color centers.