Study and Fabrication of Multi-Band Filter Film on ZnS Substrate

In order to satisfy the special requirements of IR optical instrument, multi-band filter film on the substrate of ZnS is deposited by adopting electron beam vacuum depositing method with the ion assistant deposition technology. At incident angle of 0°～25°, 660nm high reflection and 1064nm and 3～5μm high transmission are realized. ZnS and YbF3 are selected as the high and low refractive index materials, and the film structure prepared easily is getting by optimizing the film system design curve ceaselessly. The precision of thickness control has been improved by adjusting film process parameters and improving film thickness control methods. The adhesion and firmness of film and substrate has been increased by pre-coating and mixed evaporation technology, and the laser induced damage threshold of film has been improved with vacuum annealing. The deposited film can endure the environmental tests such as rain pour, salt fog, and high and low temperature etc, and meet its practical requirement.