Birefringent Filters
| Material | Crystal Quartz |
| Dimension Tolerance | +0/-0.2mm |
| Thickness Tolerance | ±0.2mm |
| Wavefront Distortion | <λ/8@632.8nm |
| Surface Quality | 20/10 scratch and dig |
| Parallelism | <5 arc seconds |
| Clear Aperture | >90% |
