The material of Calcium Fluoride has a wide rang of spectrum (from 130nm to 9400nm) and lower refractive index. They can be used as ultra-violet and infra-red optics, achromatic lenses in un-visible range.Because of the material with the characteristics of high thermal expansion coefficient and low heat conduction, they are hard to manufacture. But BTMT is able to produce commonly grade and laser grade Calcium Fluoride lenses.