Standard Tolerances
Flat Bk-7, Fused Silica and Silica Materials
| Flat Optics Specifications | Commercial Quality | Precision Quality | Laser Grade Quality | Measurement Limit |
| Surface Figure Accuracy, PTV @ 633nm | 3 waves/25mm | 1 wave | λ/4 | λ/20 |
| Surface Roughness, Angstroms RMS | – | <5 | <3 | <2 |
| Cosmetic QUALITY, Scratch-Dig | – | 40-20 | 20-10 | 5-1 |
| Center Thickness Tolerance (mm) | ±0.2 | ±0.1 | ±0.025 | ±0.005mm |
| Parallelism | – | 3' | 30" | <2" |
| Diameter Accuracy (mm) | ±0.2 | ±0.1 | ±0.025 | +0.0/-0.025 |
| Transmitted Wavefront | – | 1 wave | λ/4 | λ/20 |
Flat IR Materials
| Flat Optics Specifications | Commercial Quality | Precision Quality | Laser Grade Quality | Measurement Limit |
| Surface Figure Accuracy, PTV @ 633nm | 3 waves/25mm | 1 wave | λ/2 | λ/10 |
| Surface Roughness, Angstroms RMS | – | <7 | <5 | <3 |
| Cosmetic QUALITY, Scratch-Dig | – | 60-40 | 40-20 | 20-10 |
| Center Thickness Tolerance (mm) | ±0.25 | ±0.15 | ±0.1 | +0.0/-.1 |
| Parallelism | – | 3' | 30" | 5" |
| Diameter Accuracy (mm) | ±0.25 | ±0.15 | ±0.1 | +0.0/-.1 |
| Transmitted Wavefront/Power Cancellation, PTV@633nm | – | 2 waves | 1 wave | λ/5 |
Diamond Point Turning
| Flat Optics Specifications | Commercial Quality | Precision Quality | Laser Grade Quality | Measurement Limit |
| Surface Figure Accuracy, PTV @ 633nm | 3 waves/25mm | 1 Wave | λ/2 | λ/5 |
| Surface Roughness, Angstroms RMS | <120 | <100 | <80 | <20 |
| Cosmetic QUALITY, Scratch-Dig | 100/80 | 80/50 | 50/30 | 40/20 |
| Center Thickness Tolerance (mm) | ±0.075 | ±0.030 | ±0.010 | ±0.005 |
| Parallelism | <.020 | <.010 | <.005 | <.003 |
| Diameter Accuracy (mm) | ±0.050 | ±0.025 | ±0.010 | ±0.003 |