Calcium Fluoride is often used in spectroscopic windows and lenses due to its high transmission from 250nm to 7μm. Calcium Fluoride is also commonly found in cryogenically cooled thermal imaging systems. Its low absorption and high damage threshold makes it a popular choice for excimer laser optics. Calcium Fluoride's low refractive index allows it to be used without an antireflective coating.
| Specification | |
| Transmission Range | 0.13µm to 7.0µm |
| Density | 3.18 g/cm3 |
| Thermal Expansion | 18.85 x 10-6 /°C |
| Surface Finish | Polishes of 20-10 scratch-dig are mostly specified for use in UV & visible applications. Typical specifications for surface quality in the infrared are a 40-20 scratch dig in the 0.75 to 3µm spectral region & 60-40 scratch-dig for the 3-7µm area. |
| Surface Figure | In the UV & Visible spectral regions, surface figure ranges from 1/10 wave to 1/4 wave @ 0.6328µm. In the infrared, typical required surface figure ranges from 1/4 wave to 2 waves @ 0.6328 µm & are specified depending on the system performance requirements. |
| AR Coating Options | Available coatings for CaF2 include BBAR for 0.8 to 2.5µm, 3 to 5µm or the 1 to 5µm spectral regions. |
| Typical Applications | Cryogenically cooled thermal imaging, Astronomical, Microlithography, Excimer Laser applications. |
| Wavelength µm) | Index of Refraction (n) |
| 1.06 | 1.428 |
| 2.0582 | 1.424 |
| 4 | 1.41 |
| 5.8932 | 1.387 |
| 8.2505 | 1.344 |
| 9.4291 | 1.316 |
