Infrared Filter
Specification:
| Material | Silicon or Germanium |
| Diameter Tolerance | +0.0,-0.2 mm |
| Surface Quality | 60-40 scratch and dig |
| Clear Aperture | >85% |
| Parallelism | < 3 arc minute |
| Flatness | Power <5 fringes (2.5λ); Irregularity 1 fringe (λ/2) |
| Protective Bevel | <0.25 mm x 45° |
| Coating | Uncoated |
