Fabrication of antireflectin coating on ZnS substrate

ZnS, an significant optical material in IR regions, is applied in many opto electronic systems where a suitable antireflection coating is required to enhance the transmission. In this paper, an antireflection coating on ZnS substrate is presented. The design involves a connection layer with Zns substrate, thin Y 2O 3 film, and 4 layer stack of Ge and SiO as high and low refractive index coating matetrials, respectively. The coating conforms to environmental stability standards and shows an average transmission of 96% for a given application in 3μm~5μm range with a peak beyond 98% at 4.2μm thick ZnS substrate.