Our CO2 laser windows are made from Laser Grade ZnSe and coated with low absorbing and low reflectance coatings. Windows from other materials such as Germanium, Silicon, Zinc Sulphide (ZnS) can also be made and coated for other wavelengths.
Dimensional tolerances for standard lenses, windows and mirrors are as follows:
- Diameter: +0/-0.1 mm for most diameters, +0/-0.05 mm for 1.5″ lenses
- Centre thickness: +/-0.1 mm
- Edge thickness variation: most lenses within 0.03 mm and some within 0.05 mm
- Focal length: +/-0.5%. Some long focal singlet scanning lenses can be 1 to 2% due to highly meniscus shape
- Surface form: typically less than 1 visible fringe on a 38 mm diameter test area
- Surface roughness: within 20 Å rms
Tighter tolerances are possible on custom optics. Sometimes they are interrelated if very tight, e.g. the achievable flatness on a window can depend on the thickness (rigidity).