Si Lens
Specifications:
Material: Silicon
Diameter Tolerance: +0.00, -0.15mm(Standard), +0.00,-0.05mm(Precision)
Thickness Tolerance: +/-0.1mm
Flatness: lambda at 632.8nm
Surface Quality: 60-40 S/D
Paraxial Focus Length: +/-2%
Centration: 85% of diameter
Bevel: 0.25x45deg

Ge Lens
Specifications:
Material: Germanium
Diameter Tolerance: +0.00, -0.15mm(Standard), +0.00,-0.05mm (Precision)
Thickness Tolerance: +/-0.1mm
Flatness: lambda/2 at 632.8nm
Surface Quality: 60-40 S/D
Paraxial Focus Length: +/-2%
Centration: < 10 arc minutes
Clear Aperture: >85% of diameter
Bevel: 0.25x45deg