Fabrication of Ge-ZnS multilayered optical filters for mid-infrared applications

Germanium/Zinc Sulphide (Ge/ZnS) single and multilayers are deposited by ion assisted electron beam deposition on Silicon substrates for applications in the 2-15 µm wavelength region. Refractive indices of Ge ZnS thin films extracted from measured reflectance transmittance spectra. Several types mid-infrared filters (high-, anti-reflection coatings dichroic filters) with a number layers ranging 3 to 29 then designed deposited. The optical responses fabricated show good agreement between experimental spectra simulation case high- long-wave infrared but also low mid-wave broadband bandpass infrared.