Ideal for near-IR applications
Broadband 3 to 12 µm anti-reflection coating
Ideal for applications requiring low dispersion
Great for low power CO2 laser applications
Germanium windows are ideal for IR applications at a broad range of wavelengths, including use in lower power CO2 lasers. Germanium also has low dispersion, ideal for imaging applications. The windows feature an AR coating providing high transmission from 3 to 12 µm.
Germanium Optical Windows have good transmittance from 2 to 16 µm uncoated, and very low peak absorption, making the material an excellent candidte for use in C02 laser cavities. Germanium also has high opacity across the entire visible spectrum, making the windows ideal for applications where transmission of IR wavelengths only is desired.
The AR.20 broadband anti-reflection coating offeed with our Germanium parallel windows is effective from 3 µm to 12 µm.
| GEW | 10GE & 10SI | |
|---|---|---|
| Material | Optical Grade Germanium | Optical Grade Germanium or Optical Grade Silicon |
| Thickness | See Order Table | |
| Clear Aperture | Central 90% of diameter | Central 85% of diameter |
| Size tolerance | +0.0/-0.1 mm | ±0.20 mm |
| Thickness Tolerance | ±0.25 mm | |
| Surface Quality | 40-20 scratch-dig | |
| Surface Flatness | λ/20 @ 10.6 µm | |
| Parallelism | < 1 arc minute | < 3 arc minute |
| Coating | 3-12 µm AR, < 5% per surface 8-12 µm AR, < 2% per surface | Uncoated |
| Refractive Index | 1.765 @ 632.8 nm | Silicon: 3.42 @ 632.8 nm |
| Hardness (Knoop) | 800 kg mm-2 | Silicon: 1100 kg mm-2 |
| Young\'s modulus | 103 GPA | Silicon: 130.91 GPA |
| Thermal Limit | 59 W m-1 K-1 @ 293 K | Silicon: 163 W m-1 K-1 @ 313 K |
| Thermal expansion coefficient | 6.1 x 10-6 K-1 @ 298 K | Silicon: 2.6 x 10-6 K-1 @ 293 K |
| Model |
Diameter (mm) |
Thickness (mm) |
|---|---|---|
| GEW13AR.20 | 25.0 | 3.0 |
| GEW15AR.20 | 50.0 | 3.0 |
| GEW16AR.20 | 74.9 | 5.0 |
| 10GE20 | 25.4 | 2.0 |
| 10SI20 | 25.4 | 2.0 |