Alfa Chemistry customizes infrared optics using barium fluoride (BaF2), a crystalline compound with excellent transmittance of over 90% between 0.2 and 10 µm, making it useful for vacuum UV and long-wave infrared applications. All custom BaF2 optics are rigorously tested by skilled experts in cutting-edge metrology facilities, giving customers peace of mind that their needs will be met. Contact us as soon as possible to provide you with customer service!
Our Services
Alfa Chemistry offers a wide range of BaF2 optics including windows, lenses, prisms and ground blanks. Our optics customization options include uncoated and coated. Common optical coatings are broadband anti-reflection (BBAR) coatings designed to improve optical performance in certain wavelength bands. 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.
BaF2 Windows
The most commonly requested specifications for an BaF2 window are as follows:
| Diameter Range | 5 mm ~ 100 mm |
| Diameter Tolerance | ± 0.1 mm |
| Centre Thickness | up to 30 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 |
BaF2 Prisms
The most commonly requested specifications for an BaF2 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 |
BaF2 Ground Blanks
The most common specifications for BaF2 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:
- Thermal Imaging: Because they transmit in the MWIR and LWIR bands, BaF2 materials are frequently utilized for infrared thermal imaging.
- FTIR Spectroscopy: BaF2 is ideal for FTIR spectroscopy due to its transmission range of 200 nm to 12 µm.
- Scintillation Crystals: BaF2 is the fastest known scintillator material and is commonly used to produce fast acting. Nuclear physics and positron emission tomography (PET) applications both use BaF2 scintillators.
BaF2's Optical Properties
BaF2 is more resistant to high-energy radiation, such as gamma and X-rays, than other fluoride compounds. It can function at 800°C when the environment is dry. BaF2 deteriorates at 500 °C when exposed to moisture, particularly in the vacuum ultraviolet (VUV) range of performance. Barium fluoride should also be handled carefully because it is a dangerous substance.
Fig 1. X-ray emission spectra of BaF2. (Kumar V, et al. 2021)
Below is a quick description of BaF2's optical characteristics. For more information on the properties of BaF2 materials please click here.
| Transmission Range | 0.15 to 12 µm |
| Refractive Index | 1.45@5 µm |
| Melting Point | 1386 ℃ |
| Density | 4.89 g/cm3 |
| Hardness | Knoop 82 with 500g indenter |
| Operating Temperature | < 800℃ in dry environment |
If you need technical advice, please contact our technical team to learn more about our high-quality services.
Reference
- Yadav A, et al. (2021). "A Review on X-ray Excited Emission Decay Dynamics in Inorganic Scintillator Materials." Photonics. 8(3): 71.