Calcium fluoride (CaF2), a crystalline optical material with good transmission in the UV to long-wave IR region, is used by Alfa Chemistry to create customized infrared optics. Low absorption, a high uniformity of refractive indices, chemical inertness, a high damage threshold, physical stability, high mechanical strength, and insolubility in water are just a few of the numerous advantageous characteristics of CaF2.
All custom CaF2 optics are rigorously tested by skilled experts at cutting-edge metrology facilities, giving customers the peace of mind that their needs will be met. Contact us as soon as possible for your customer service!
Our Services
Alfa Chemistry offers a high quality customization service for CaF2 components, including lenses and windows, manufactured to your custom specifications. Different grades of calcium fluoride are available.
- UV grade, with enhanced performance in UV (and VUV) wavelengths.
- IR grade or standard grade, which performs well in the IR region.
- Raman grade, which shows minimal fluorescence.
Our custom service includes uncoated and coated CaF2 optical options. Available optical coatings are broadband anti-reflective coatings. The table that follows lists our typical manufacturing requirements. Our skills are constantly growing, so if your need is not covered above, please get in touch with our technical sales team, who will be able to help you out because we have years of experience in this area.
CaF2 Windows
The most commonly requested specifications for an CaF2 window are as follows:
| Diameter Range | 5 mm ~ 200 mm |
| Diameter Tolerance | ± 0.1 mm |
| Centre Thickness | up to 50 mm |
| Centre Thickness Tolerance | ± 0.05 mm |
| Clear Aperture | 90% |
| Centration Tolerance | 1 arc minute |
| Form Error | better than λ/4 (633nm) over aperture |
| Surface Radius Tolerance | 1 fringe over aperture |
| Linear Dimension | up to 200 mm |
| Linear Tolerance | ± 0.1 mm |
| Angular Tolerance | 5 arc minutes |
| Edge Finish | ground |
| Chamfer | 0.3x0.3@45° |
| Surface Quality | 40-20 scratch/ dig |
CaF2 Prisms
The most commonly requested specifications for an CaF2 prism are as follows:
| Length of Hypotenuse | up-to 50 ± 0.1 mm |
| Length of Sides | up-to 50 ± 0.1 mm |
| Thickness | 30 ± 0.05 mm |
| Angle Tolerance | better than 1 arc minute |
| Edge Finish | ground, blacked |
| Clear Aperture | 90% of entrance dimensions |
| Chamfer | 0.3x0.3@45° |
| Form Error | better than λ/4 @633 nm |
| Surface Quality | 40-20 scratch/dig |
CaF2 Ground Blanks
The most common specifications for CaF2 ground blanks are as follows.
| Diameter Range | less than 5 mm to 200 mm |
| Diameter Tolerance | better than ± 0.5 mm |
| Centre Thickness | up to 50 mm |
| Centre Thickness Tolerance | better than ± 0.5 mm |
| Clear Aperture | 90% |
| Linear Dimension | up to 200 mm |
| Linear Tolerance | better than ± 0.5 mm |
| Angular Tolerance | better than 10 arc minutes |
| Edge Finish | fine ground N6 |
| Chamfer | 0.3x0.3@45° |
Applications:
- Excimer lasers: The substrate for excimer laser reflectors is frequently CaF2. Because it absorbs less UV light, UV grade calcium fluoride is suggested for excimer laser applications.
- Cryogenically Cooled Thermal Imaging: Cryogenic cooling is occasionally used to keep infrared detectors on thermal imaging systems at a constant low temperature to reduce thermal noise. Most often, calcium fluoride is employed in these detectors. In FLIR and thermal imaging applications, calcium fluoride of standard IR grade offers the finest results.
- Raman Spectroscopy: Calcium windows are widely used as spectral windows.
CaF2's Optical Properties
CaF2 has favorable thermomechanical and optical characteristics. CaF2 is regarded as one of the toughest fluoride crystal materials overall. CaF2 is the perfect substrate for lenses used in high-performance laser systems because of its high refractive index homogeneity and minimal absorption. The high homogeneity means minimal scattering and distortion of the wavefront.
CaF2 can operate at a maximum temperature of 800 °C in dry conditions. CaF2 has a low absorption rate and a high refractive index. High temperatures can cause thermal shock to it.
Below is a quick description of CaF2's optical characteristics. For more information on the properties of CaF2 materials please click here.
| Transmission Range | 0.13 to 10 µm |
| Refractive Index | 1.39908@5 µm |
| Melting Point | 1360 °C |
| Density | 3.18 g/cm3 |
| Hardness | Knoop 158.3 (100) with 500g indenter |
| Operating Temperature | < 800°C in dry conditions |
If you need technical advice, please contact our technical team to learn more about our high-quality services.