Alfa Chemistry can customize infrared optical components using gallium arsenide (GaAs) material, an IR-transmissive, semi-insulating, and insoluble material that shares many mechanical properties with germanium. Wherever endurance and hardness are required, GaAs is frequently employed. All custom GaAs 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 soon for your customer service!
Our Services
Alfa Chemistry provides high-quality GaAs component customization with windows, lenses, and other components that can be produced to exact requirements. We provide both coated and uncoated optical options, including coatings with diamond-like carbon (DLC) or broadband reduced reflection (BBAR). Our typical fabrication needs are listed in the table below. If your needs are not covered here, please get in touch with our technical sales team. We have years of experience in this industry and are always working to improve our skills.
GaAs Windows
The most commonly requested specifications for an GaAs window are as follows:
| Diameter Range | 5 mm ~ 100 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 100 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 |
GaAs Prisms
The most commonly requested specifications for an GaAs 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 | 0.2 fringe from test flat |
| Surface Quality | 40-20 scratch/dig |
GaAs Ground Blanks
The most common specifications for GaAs ground blanks are as follows.
| Diameter range | less than 5 mm to 100 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 100 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:
- Forward Looking Infrared (FLIR) Systems: Since GaAs optical lenses and windows transmit and endure well in both the MWIR (3~5 µm) and LWIR (80~12 µm) bands, they are frequently employed in FLIR systems.
- CO2 Lasers: Due to its longevity, GaAs can be employed in medium- to high-power CO2 lasers. It can't be used with He-Ne lasers and won't transmit in the visible spectrum.
- High-Efficiency Solar Cells: GaAs is the material that converts solar energy into electricity most effectively. It is extremely resistant to higher temperatures while being light-sensitive.
GaAs's Optical Properties
Undoped semi-insulating GaAs can be employed in lenses and beam splitters because of its high terahertz and mid-infrared transmittance. Due to their nonlinear optical characteristics, GaAs crystals can be employed as terahertz radiation generators in terahertz photonics. GaAs can also show linear electro-optical phenomena. An external electric field has an impact on the refractive index.
Fig 1. Refractive index(a), extinction coefficient(b), transmittance(c) and absorption coefficient(d) of GaAs. (Akinlami J. O, et al. 2013)
In addition, GaAs is a very durable material. In addition to its high hardness, it is chemically stable and non-hygroscopic. GaAs has an optical band gap with an intrinsic edge of 0.87 µm. GaAs has low absorbance at a transmittance of about 40% between 2 and 15 µm and can be applied to BBAR coatings to improve its spectral performance.
Below is a quick description of GaAs's optical characteristics. For more information on the properties of GaAs materials please click here.
| Transmission Range | 1 to 16 µm |
| Refractive Index | 3.2727@0.33 µm |
| Melting Point | 1511 °C |
| Density | 5.315 g/cm3 |
| Hardness | Knoop 750 |
If you need technical advice, please contact our technical team to learn more about our high-quality services.
Reference
- Akinlami J. O, et al. (2013). "Optical Properties of GaAs." Journal of Semiconductors. 34(3): 032002.