Silicon (Si) Windows
Excellent IR Transmission: CZ silicon is optimal for MWIR (3-5 μm) applications, while FZ silicon is suitable for LWIR (8-12 μm) due to its reduced absorption at 9 μm.
High Thermal Conductivity: Silicon’s high thermal conductivity makes it suitable for high-power laser applications.
Low Density: With a density of 2.329 g/cm³, silicon is lighter than germanium (Ge) and zinc selenide (ZnSe), making it ideal for weight-sensitive designs.
Durability: Silicon windows are chemically and abrasion-resistant, making them durable and suitable for challenging environments.
High Hardness: Silicon is the hardest material that is transparent to light in the 1000-1600 nm range, providing excellent durability and scratch resistance.
Applications: Lasers, IR imaging, weight-sensitive designs, etc.
Silicon (Si) Windows from Kingwin Optics are crafted from high-quality optical grade silicon, available in both Czochralski (CZ) and Float Zone (FZ) silicon. These windows are designed for infrared (IR) applications, particularly in the mid-wave infrared (MWIR) and long-wave infrared (LWIR) spectral regions. With their excellent thermal conductivity, low density, and robust chemical and abrasion resistance, silicon windows are ideal for a variety of demanding environments and applications.
Key Properties of Silicon Windows:
| Materials | Silicon crystals |
| Aperture | >90% |
| Dimension Tolerance | +0.0/-0.2mm |
| Thickness Tolerance | +/-0.1mm |
| Surface Quality | 60/40 S/D |
| Chamfer | 0.3-0.5mmx45 degree |
| Coating | AR/AR or DLC/AR |
| Transmission Range | 1.2 to 15 μm |
| Refractive Index | 3.4223 @ 5 μm (1) (2) |
| Reflection Loss | 46.2% at 5 μm (2 surfaces) |
| Absorption Coefficient | 0.01 cm-1 at 3 μm |
| Reststrahlen Peak | n/a |
| dn/dT | 160 x 10-6 /°C (3) |
| dn/dμ = 0 | 10.4 μm |
| Thermal Conductivity | 163.3 W m-1 K-1 at 273 K |
| Melting Point | 1420 °C |
| Hardness | Knoop 1150 |
| Thermal Expansion | 2.6 x 10-6 / at 20°C |
| Dielectric Constant | 13 at 10 GHz |
| Specific Heat Capacity | 703 J Kg-1 K-1 |
| Density | 2.33 g/cc |
| Youngs Modulus (E) | 131 GPa (4) |
| Shear Modulus (G) | 79.9 GPa (4) |
| Bulk Modulus (K) | 102 GPa |
| Apparent Elastic Limit | 124.1MPa (18000 psi) |
| Poisson Ratio | 0.266 (4) |
| Elastic Coefficients | C11=167; C12=65; C44=80 (4) |
| Solubility | Insoluble in Water |
| Molecular Weight | 28.09 |
| Class/Structure | Cubic diamond, Fd3m |
Advantages of Silicon Windows:
- Excellent IR Transmission: CZ silicon is optimal for MWIR (3-5 μm) applications, while FZ silicon is suitable for LWIR (8-12 μm) due to its reduced absorption at 9 μm.
- High Thermal Conductivity: Silicon’s high thermal conductivity makes it suitable for high-power laser applications.
- Low Density: With a density of 2.329 g/cm³, silicon is lighter than germanium (Ge) and zinc selenide (ZnSe), making it ideal for weight-sensitive designs.
- Durability: Silicon windows are chemically and abrasion-resistant, making them durable and suitable for challenging environments.
- High Hardness: Silicon is the hardest material that is transparent to light in the 1000-1600 nm range, providing excellent durability and scratch resistance.
Coating Options:
To enhance the performance of silicon windows, various anti-reflection (AR) coatings are available:
- DLC/AR Coating: Diamond-Like Carbon (DLC) coating on one side and AR coating on the other side for superior durability and transmission.
- AR/AR Coating: Anti-reflection coatings on both sides to minimize reflection and maximize transmission efficiency.
Applications:
- Lasers: High thermal conductivity and excellent IR transmission make silicon windows ideal for laser systems.
- IR Imaging: Suitable for mid-wave and long-wave infrared imaging systems.
- Weight-Sensitive Designs: Low density makes silicon windows suitable for aerospace and other applications where weight is a critical factor.
- Challenging Environments: Chemical and abrasion resistance ensure durability in harsh conditions.
Custom and Off-the-Shelf Solutions:
Kingwin Optics provides custom silicon windows tailored to meet specific needs. The windows can be manufactured in various dimensions, with a maximum diameter of 300 mm. Custom coatings are also available to optimize performance for different applications.
Silicon Windows from Kingwin Optics provide superior performance for a wide range of IR applications. With excellent transmission properties, high thermal conductivity, and robust chemical and abrasion resistance, these windows are ideal for demanding environments. Customizable dimensions and coatings ensure that your specific needs are met with precision and quality.
