... thermal imaging lenses are transmissive optics, ideal for IR applications Si Lenses, Silicon Lens Silicon is used as an optical window ... (ZnSe)Zinc Sulfide (ZnS)ZnSZinc Sulfide MultiSpectral (ZnS MS)Silicon (Si)Calcium Flouride (CaF2)amorphous material transmitting infrared radiation (AMTIR)Geometries ... )high durability, medium efficiency BBARdiamond-like coatings (DLC)filters Si Lenses, Silicon Lens