Barium fluoride (BaF2) has nearly 90% transmitance in the wavelength of 200-9500 nm. t has a widest broadband opticatransmittance and can transmit from far ultraviolet to long wave infrarec, therefore it can be used in various applications, suchas infrared spectroscope. The low refractive index of barum fluoride is 1.48, which can provide high transmitance withoutanti reflection film, In a dry environment, calcium fluoride windows can endure up to 800 degrees of ambient temperature, butexoosure to water for a ong time wil reduce the transmitance in the range of vacuum ultraviolet icht, However, comparecto the calcium fuorice window. the resistance of the barum fuoride wincow to the moisture is ower, and the BaF2 wincowis the most resistant to high energy radiation, but it has a lower transmission of UV. The knoop hardness of BaF2 is 82, andit is very sensitive to thermal shock. lt is usually applied to cryogenic imaging system, lens in space optical system and laseroptical system, beam spliter, flter, prism and window. The material has a certain degree of water solubility which is suitableto be used in dry environment.
