Silicon (Si) Lenses
Broad IR Transmission: Silicon lenses are effective in both MWIR and LWIR ranges, making them versatile for various IR applications.
Low Density: Silicon has a low density (2.33 g/cm³), approximately half that of Germanium (Ge) or Zinc Selenide (ZnSe), making it ideal for weight-sensitive applications.
Hardness and Durability: Silicon is harder and less brittle than Germanium, offering better durability and resistance to mechanical stresses.
Chemical Resistance: Silicon exhibits high chemical resistance, ensuring longevity and stability in harsh environments.
Cost-Effective: Silicon is relatively inexpensive compared to other IR materials, providing a cost-effective solution for IR optics.
Applications: IR optics, thermal imaging, laser systems, military optics, medical equipment.
Silicon (Si) Lenses are critical components for manipulating light in the infrared (IR) spectrum. Manufactured using optical grade silicon, these lenses are used for light collimation, direction, and other optical manipulations. There are two primary types of silicon used for these lenses: Czochralski (CZ) silicon for the 3-5μm MWIR range, and Float Zone (FZ) silicon for the 8-12μm LWIR range.
Physical and Optical Properties:
| Materials | Silicon crystals |
| Diameter Tolerance | -0.01/-0.03mm |
| Thickness Tolerance | +/-0.03mm |
| Surface Quality | 60/40 S/D |
| Chamfer | 0.1-0.3mmx45 degree |
| Coatings | AR/AR@3-5micro DLC/AR@3-5micro |
| Transmission Range | 0.12μm to 15 μm and and 30μm to >100 μm (1) |
| 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 |
| Elastic Coefficients | C11=167; C12=65; C44=80 (4) |
| Apparent Elastic Limit | 124.1MPa (18000 psi) |
| Poisson Ratio | 0.266 (4) |
| Solubility | Insoluble in Water |
| Molecular Weight | 28.09 |
| Class/Structure | Cubic diamond, Fd3m |
Advantages of Silicon Lenses:
- Broad IR Transmission: Silicon lenses are effective in both MWIR and LWIR ranges, making them versatile for various IR applications
- Low Density: Silicon has a low density (2.33 g/cm³), approximately half that of Germanium (Ge) or Zinc Selenide (ZnSe), making it ideal for weight-sensitive applications.
- Hardness and Durability: Silicon is harder and less brittle than Germanium, offering better durability and resistance to mechanical stresses.
- Chemical Resistance: Silicon exhibits high chemical resistance, ensuring longevity and stability in harsh environments.
- Cost-Effective: Silicon is relatively inexpensive compared to other IR materials, providing a cost-effective solution for IR optics.
Considerations for Use:
- Transmission Range Limitations: The type of silicon used (CZ or FZ) determines the effective transmission range, so selection must be application-specific.
- Thermal Properties: Silicon’s high thermal conductivity and low thermal expansion coefficient make it stable under varying temperature conditions, but careful thermal management is still required in high-power applications.
Applications:
- IR Optics: Utilized in various IR imaging and detection systems for security, surveillance, and industrial applications.
- Thermal Imaging: Integrated into thermal cameras and systems for accurate temperature measurement and monitoring.
- Laser Systems: Used in high-power laser systems for collimation and focusing of laser beams.
- Military Optics: Applied in military equipment for IR detection, targeting, and imaging.
- Medical Equipment: Essential in medical diagnostic devices operating in the IR spectrum.
Custom Solutions:
Kingwin Optics offers a range of custom silicon lenses tailored to specific needs. These lenses are available in various shapes and sizes, with specialized coatings to enhance their performance in specific applications. Kingwin Optics ensures high-quality and precision in their silicon lenses, making them suitable for demanding optical applications.
Silicon lenses are versatile and high-performing optical components suitable for a wide range of IR applications. Their broad transmission range, low density, hardness, and chemical resistance make them ideal for use in IR optics, thermal imaging, laser systems, and more. With custom solutions from Kingwin Optics, silicon lenses can be tailored to meet specific requirements, ensuring optimal performance in various demanding environments.
