The silver-based films have highest reflectivity from VIS to IR, however, the environmental stability of Ag thin films is poor and susceptible to co2osion with reflectivity reduction. Different thickness ratio of Ta2O5-SiO2 nanolaminate films were prepared by ion beam assisted electron beam evaporation (IAD). The effective refractive index and residual stress of the films were calculated. Furthermore, nanolaminate protection layers and conventional two-layers type protection layers were designed and fabricated on silver layer after selection of nanolaminate films with Ta2O5 thickness accounting for 75%. Multi-band high reflectivity targets were achieved and the residual stress of the two silver-based films were similar. After 24 hours of humidity test, the reflectance redshift of nanolaminate protection silver-based films was less than conventional two-layers type protection silver-based films. After 144 hours of humidity test, compared with conventional two-layers type protection silver-based films, the corrosion defects color depth of nanolaminate protection silver-based films was less and the defects size of nanolaminate protection silver-based films was smaller. Combined with TEM observation results after combining FIB sample preparation, the nanolaminate protection layers possessed higher density and it could perform better in aspect of environmental durability.
