Zinc selenide (ZnSe) is a yellow transparent polycrystalline material. Because of its extremely low absorption coefficient at 10.6 u m band, it has become the preferred optical material for high-power carbon dioxide lasers. Because of its excellent optical properties, it is widely used as window, lens and prism of high-definition forward-looking infrared system. In addition, it is also widely used in different optical systems in the whole transparent band range.