Germanium (Ge) Windows
Broad IR Transmission Range: Germanium windows provide excellent transmission in the 2 µm to 14 µm range, making them ideal for MWIR and LWIR applications.
Low Dispersion: The low optical dispersion of Germanium ensures minimal distortion and accurate transmission of IR signals.
Ruggedness: Germanium is more rugged compared to other IR materials, providing durability and reliability in demanding environments.
Chemical Inertness: High chemical inertness makes Germanium windows resistant to harsh chemical environments.
High Refractive Index: With a high refractive index, AR coatings are necessary to achieve high transmission efficiency.
Applications: Thermal cameras, IR imaging, long-pass filters, protective windows, etc.
Germanium (Ge) Windows are highly valued in infrared spectrum applications due to their extensive IR transmission range and opacity in the visible spectrum. These windows offer broadband transmission across a wide range of infrared wavelengths from 2 µm to 14 µm, making them particularly effective in the mid-wave infrared (MWIR) and long-wave infrared (LWIR) regions.
Key Properties of Germanium Windows:
| Transmission Range | 2 µm to 14 µm |
| Refractive Index (n) | 4.0 at 10 µm |
| Knoop Hardness | 780 kg/mm² |
| Thermal Conductivity | 60 W/m·K |
| Density | 5.33 g/cm³ |
| Transmission Efficiency | >45% (2-14 µm, uncoated); >95% (coated) |
| Max Diameter | 300 mm |
| Chemical Inertness | High |
| Operational Temperature Range | Below 90°C for IR transparency |
Advantages of Germanium Windows:
- Broad IR Transmission Range: Germanium windows provide excellent transmission in the 2 µm to 14 µm range, making them ideal for MWIR and LWIR applications.
- Low Dispersion: The low optical dispersion of Germanium ensures minimal distortion and accurate transmission of IR signals.
- Ruggedness: Germanium is more rugged compared to other IR materials, providing durability and reliability in demanding environments.
- Chemical Inertness: High chemical inertness makes Germanium windows resistant to harsh chemical environments.
- High Refractive Index: With a high refractive index, AR coatings are necessary to achieve high transmission efficiency.
Temperature Sensitivity:
- Thermal Considerations: Germanium becomes opaque in the IR spectrum at temperatures above 90°C. Caution is required when using Ge windows in high-temperature applications to avoid loss of transparency.
Coating Options:
To enhance transmission, various anti-reflective (AR) coatings are available:
- DLC (Diamond Like Carbon) Coating
- AR Coating @ 3-5 µm
- AR Coating @ 8-12 µm
- BBAR Coating @ 3-12 µm
Applications:
- Thermal Cameras: Used as protective windows to shield sensitive components while ensuring clear IR transmission.
- IR Imaging and Sensing: Ideal for applications requiring precise and distant IR imaging and sensing.
- Long-Pass Filters: Effective for filtering wavelengths above 2000 nm.
Custom and Off-the-Shelf Solutions:
Kingwin Optics offers both off-the-shelf and custom Germanium Windows with diameters up to 300mm. Off-the-shelf options come with individually listed transmission curves and specifications. Custom windows can be fabricated with high precision and tailored coating sets according to specific requirements.
Germanium windows from Kingwin Optics provide superior performance for infrared applications, with a broad transmission range, ruggedness, and high chemical inertness. Customizable options and various AR coatings ensure optimal transmission efficiency for specific needs. These windows are an excellent choice for thermal cameras, IR imaging, and other demanding IR applications.
