Infrared antireflection film coated on window of infrared detector with IAD

Zinc sulfide(ZnS) is often used as the protecting window of infrared detectors while its transmittance for 7～12 μm light is not high.In order to enhance the optical transmissivity and the mechanical strength,two kinds of wide band infrared antirgflective film were designed and deposited with the ion-beam assisted deposition(IAD) system.YF3 and YbF3 were selected to be the coating materials after studying several kinds of materials.Performances of the two products were tested and compared,Results show that the transmittances of both the film are above 90% in 7～12 μm range.The mechanical strength of the YF3-ZnS film is poor than that of the YbF3-ZnS.