The physical and chemical properties of calcium fluoride
Hardness: The Mohs hardness of calcium fluoride is relatively low, about 4, which means that care should be taken during handling and processing to avoid scratches.
Thermal stability: It has good thermal stability and thermal conductivity, and can withstand temperature changes within a certain range without fracture.
Chemical stability: Calcium fluoride has good resistance to most acids and bases, but is soluble in hydrofluoric acid.
Refractive Index: Calcium fluoride has a relatively low refractive index of approximately 1.434 in the visible light region, making it very useful in manufacturing low dispersion optical components.
Calcium fluoride (CaF2) is an important optical material widely used in many high-precision optical applications due to its unique optical properties and chemical stability. The crystal structure of calcium fluoride gives it good transparency over a wide spectral range, from ultraviolet (approximately 157 nanometers) to far-infrared (approximately 8-10 micrometers), and even up to around 12 micrometers in some cases. This wide transmission range, combined with other excellent physical and chemical properties, makes calcium fluoride an ideal material for manufacturing various optical components, such as lenses, prisms, windows, and base materials for optical coatings.
Optical Applications
Ultraviolet optical system: Due to its excellent transparency in the deep ultraviolet region, calcium fluoride is widely used in ultraviolet lithography, ultraviolet spectroscopy, and other optical systems that require deep ultraviolet transmission.
Infrared optical system: The application of calcium fluoride is equally important in infrared optical systems, especially in thermal imaging, infrared spectroscopy, and military night vision equipment.
High power laser: The low absorption rate and high laser damage threshold of calcium fluoride make it suitable for windows and lenses in high-power laser systems, especially in ultraviolet laser applications.
Optical coating substrate: Calcium fluoride is also commonly used as a substrate material for optical coatings to improve the performance of optical components.
The wide spectral transmission range, good thermal stability, and chemical stability of calcium fluoride make it an ideal choice for many high-precision optical applications. However, its lower hardness and fragility require careful handling during processing and use. With the development of optical technology, the demand for high-performance optical materials such as calcium fluoride will continue to grow.