Alfa Chemistry customizes infrared optical components using the commonly used material sapphire (Al2O3), a very important optical material widely used in UV, visible and near-infrared applications due to its high light transmission and excellent mechanical strength properties at high temperatures. All of our custom sapphire optics are rigorously tested by skilled experts at cutting-edge metrology facilities, giving our customers the peace of mind that their needs will be met. Contact us for your customer service as soon as possible!
Our Services
Alfa Chemistry provides high quality sapphire optics services, including windows, lenses, prisms, etc., based on specific customer requirements. We can provide coated or uncoated optics with broadband anti-reflective coatings. The table below lists our typical manufacturing requirements. If your requirements fall outside of the above, please contact our technical sales team who will be able to assist you as we have many years of experience in this field.
Sapphire Windows
| Diameter Range | 5 mm ~ 300 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 120 mm |
| Linear Tolerance | ± 0.1 mm |
| Angular Tolerance | 5 arc minutes |
| Edge Finish | ground, blacked |
| Chamfer | 0.3x0.3@45° |
| Surface Quality | 40-20 scratch/ dig |
Sapphire Prisms
| Length of Hypotenuse | up-to 120 ± 0.1 mm |
| Length of Sides | up-to 100 ± 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 | 60-40 scratch/dig |
Sapphire Ground Blanks
| Diameter Range | less than 5 mm to 300 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 300 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:
- Protective windows: Due to their durability, scratch resistance, and chemical inertness, sapphire optics are frequently employed as protective windows for scientific equipment. Deep sea applications frequently use sapphire domes and windows.
Sapphire's Optical Properties
Sapphire possesses impressive optical properties including extreme hardness, high transmission, chemical resistance, high melting point, high thermal conductivity, minimal thermal expansion, high dielectric constant, and high modulus of rupture. Sapphire has excellent transmission in the ultraviolet to near-infrared wavelengths. Due to its chemical inertness to acids, bases, and water as well as its thermal tolerance up to 1000 ℃, sapphire is suited for hostile conditions.
Depending on the direction of the crystal, sapphire is slightly birefringent. The c-axis must be cut parallel to the optical axis in order to remove birefringent sapphires. The sapphire will glow under UV light if the crystal lattice contains impurities like iron (Fe) or chromium (Cr). The standard methods of polishing sapphire, which is the second-hardest crystal after diamond, are highly challenging. It's not usually possible to finish sapphires with high optical quality.
Fig 1. Optical absorption of Ag þ implanted sapphire crystal. (Kozakiewicz A, et al. 2012)
Below is a quick description of sapphire's optical characteristics. For more information on the properties of sapphire materials please click here.
| Transmission Range | 0.17 to 5.5 µm |
| Refractive Index | No 1.75449; Ne 1.74663 @ 1.06µm |
| Melting Point | 2040 °C |
| Density | 3.97 g/cm3 |
| Hardness | Knoop 2000 with 2000g indenter |
If you need technical advice, please contact our technical team to learn more about our high-quality services.
Reference
- Kozakiewicz A, et al. (2012). "Ion-Beam-Synthesized Colloidal Silver Nanoclusters in Crystalline Sapphire as Third-Order Optical Material." IEEE Photonics Journal. 4(1): 205-214.