Calcium fluoride Window CaF2 Window
Calcium fluoride (CaF2) has a high transmittance between ultraviolet to mid-infrared (250nm~7um), so it is widely used in the manufacture of prisms, windows and lenses, etc., in some applications with a wide spectral range, it can be used directly without coating, especially it has small absorption and high laser threshold, which is very suitable for use in excimer laser optical systems.
The calcium fluoride window (CaF2 window) produced by Optic-Well has a diameter range of 5~150mm, a surface accuracy of usually up to 40/20, and a surface flatness of: λ/10@633nm (the ratio of thickness to diameter of the lens needs to meet the processing ratio). Calcium fluoride (CaF2) is ideal for UV 200nm to IR 7μm applications. It has a high damage threshold and low absorption.
It is an excellent choice for FTIR analysis, excimer laser systems, and is commonly used as a spectral window and thermal imaging system. AR coatings are used to increase transmission at infrared or ultraviolet wavelengths, as well as other specified directions to cut to <100> <110> <111 >. Processing of other optical grades of single and polycrystalline CaF2, including VUV and Raman grades.
Here is the basic properties of CaF2 you can see:
| CaF2 | Physical Properties |
| Density(g/m³） | 3.18 |
| Melting Point(℃) | 1360 |
| Dielectric constant | 6.76＠1HMZ |
| CTE (1/℃) | 18.85×１０－６＠２９８Ｋ |
| Bulk modulus (Gpa) | 82.71 |
| Coefficient of thermal conductivity (J/.ｍ.ｓ) | 9.71 |
| Specific heat capacity (J/g.k) | 0.854 |
| Knoop (kg/mm２) | 158.3 |
| Tensile modulus (Gpa) | 75.8 |
| Poisson ratio | 0.26 |
| Optical Properties | |
| Wavelength | 130nm~10000nm |
| The absorption coefficient (l/cm) | 5.4×１０－２＠5000ｎｍ |
