Zinc selenide (Znse) is a kind of yellow transparent polytropism material, whose general crystallization pellet size is 70µm and transmitting scope is 0.5-15 µm. Generated from CVD method, Znse has little impurity absorption and extremely low scattering loses. Due to the low absorption to 10.6 µm wave length light, it becomes the first choice to manufacture the optical component for high power CO2 laser system. In addition, it is also commonly used in different optical systems within its entire transmitting wave band.

Due to the high endurance to the thermal shock, Znse becomes the best optical material for the high power CO2 laser system. As 2/3 hard as multi-spectrum ZnS, Znse is easily to get scratched. Plus its high refractive index, it needs to be coated with rigid thin film to get protected and to obtain a higher transmissibility. In its commonly used spectrum scope, Znse has very low dispersion. When used to make the high power laser components, its bulk absorption and inner structure flaw need to be kept in check, and the highly skilled coating and the lowest destructive polishing are also required.