Sapphire substrates $ windows are applied as circuit substrates, epitaxial substrates, oiented substrates to GaN, GaAs. Sapphire possesses nice light transmission in 0.2~5.50um wave band, and the infrared ray transmission is hardly influenced by temperature, so the optical components made of sapphire are fully applied to mulitary infrared equipment, obervation window viewport for high temperature furnances, windows for counters, and scanner etc.