Hardened CVD Zinc Selenide for FLIR Windows.
Final technical rept. 29 Apr 74-29 Apr 75,
RAYTHEON CO WALTHAM MASS RESEARCH DIV
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The significance of this exploratory development program to the Air Force is the demonstration that the CVD process can be used to increase the hardness of optical meterials such as zinc selenide and sulfide by the use of dopants such as aluminum and silicon. Increases in Knoop hardness of 50 to 100 percent were realized, although some degradation in optical properties was noted, particularly at visible wavelengths. It was also demonstrated that the CVD process can be used to deposit a thin adhering layer of zinc sulfide or hardened sulfide or selenide to a polished zinc selenide substrate. Close to theoretical transmittance was achieved. Composite structures were also fabricated by adhesively bonding polished thin layers onto a zinc selenide substrate. In this case, the transmittance was limited by internal reflectance and impurity absorptions of the adhesive. Further work on this concept is required before usable hardware is attained.
- Infrared Detection and Detectors