The 20QB20 Interferometer Flat is ideally suited for use in a laboratory interferometer or as a quality assurance standard. To ensure long-term thermal stability and mechanical accuracy. This 2 inch (50.8 mm) diameter, 12.7 mm thick optic is polished from select UV fused silica. In order to double the utility of the optic, both faces are polished to the same λ/10 figure. Internal fringe patterns are virtually eliminated by a 30 arc min wedge between faces. Surface interferograms, that allow error mapping, are shipped with each flat.
| Model | 20QB20 |
|---|---|
| Material | UV Grade Fused Silica |
| Diameter | 2.0 in. (50.8 mm) |
| Thickness | 0.50 in. (12.7 mm) |
| Antireflection Coating | Uncoated |
| Surface Quality | 10-5 scratch-dig |
| Surface Accuracy | λ/10 @ 632.8 nm |
| Clear Aperture | Central 80% of diameter |
| Wedge | 30 ±5 arc min |
| Diameter Tolerance | +0/-0.25 mm |
| Thickness Tolerance | ±0.5 mm |
| Chamfers | 0.38–1.14 mm face width |
| Chamfers Angle/Tolerance | 45° ±15° |
| Cleaning | Non-abrasive method, acetone or isopropyl alcohol on lens tissue recommended |
