Antireflective films optimization of ZnS ceramics infrared windows

The transmittance characteristics of ZnS ceramics with infrared (IR) (3 - 5 and 8 - 12 ?m) antireflective coatings are studied. The film designs are optimized with programmed software. A double-side and double-layer scheme is employed. Two different double-layers with proper parameters are coated onto each side of a ZnS substrate. The measurement methods for transmittance are investigated. The measured transmittance for IR (3 - 5 and 8 - 12 ?m) surpasses 70%.