Description
Calcium Fluoride is used for optical windows, lenses and prisms in the 0.15 µm – 9 µm (ultraviolet to infrared) regions. The low power absorption has made this material attached to wide use in high power laser optics. Polished surfaces are stable and will last several years under normal conditions. Due to its composition, CaF2 has a much longer usable lifetime than most materials operating in fluorine environments.
Calcium Fluoride, which is grown by vacuum Stockbarger technique, has a low refractive index, hence can be used without anti-reflection coating. Material for IR use is grown using naturally mined fluorite, in large quantities at relatively low cost.
| BASE PROPERTIES | ||
| PARAMETER | VALUE | |
| OPTICAL | ||
| Transmission Range | 0.13 to 10 microns | |
| Refractive Index | 1.39908 at 5 microns | |
| Reflection Loss | 5.4% at 5 microns (2 surfaces) | |
| Restrahlen Peak | 35 microns | |
| dN/dT | -10.6 x 10-6e/℃ | |
| PHYSICAL | ||
| Density | 3.18 g/cm3 | |
| Melting Point | 1360 ℃ | |
| Thermal Conductivity | 9.71 W/(m*K) | |
| Thermal Expansion | 18.85 x 10-6e/℃ | |
| Hardness | Knoop 158.3 kg/mm2 (100) | |
| Specific Heat Capacity | 854J/(kg K) | |
| Dielectric Constant | 6.76 at 1MHz | |
| Young’s Modulus (E) | 75.8 GPa | |
| Shear Modulus (G) | 33.77 GPa | |
| Bulk Modulus (K) | 82.71 GPa | |
| Elastic Coefficients | C11=164 MPa, C12=53 MPa, C44=33.7 MPa | |
| Apparent Elastic Limit | 36.54 MPa | |
| Poisson Ratio | 0.26 | |
