The 20D20DM.4 Laser Line Dielectric mirror is a highly efficient reflector optimized for the 632.8 nm wavelength. This 2 inch (50.8 mm) diameter mirror is made from a 12.7 mm thick Borofloat® 33 substrate. Borofloat has low thermal expansion and is an excellent substrate for most applications. The DM.4 coating is designed for use with HeNe lasers and has a center wavelength of 632.8 nm. The coating achieves greater than 99% reflectance, from 0–45° angle of incidence, for any polarization. This multilayer dielectric coating is extremely durable, making it resistant to damage from repeated cleaning. This mirror has a λ/10 surface flatness and a 15-5 surface quality.
| Model | 20D20DM.4 |
|---|---|
| Mirror Shape | Round |
| Wavelength Range | 632.8 nm |
| Diameter | 2.0 in. (50.8 mm) |
| Thickness | 0.5 in. (12.7 mm) |
| Material | Borofloat 33 or equivalent |
| Coating Type | Laser Line Dielectric |
| Surface Quality | 15-5 scratch-dig |
| Coating Code | DM.4 |
| Clear Aperture | ≥central 80% of diameter |
| Reflectivity | Rs, Rp>99% @ 632.8 nm |
| Angle of Incidence | 0-45° |
| Surface Flatness | λ/10 at 632.8 nm over the clear aperture |
| Chamfers | 0.38–1.14 mm face width |
| Chamfers Angle/Tolerance | 45° ±15° |
| Diameter Tolerance | +0/-0.13 mm |
| Thickness Tolerance | ±0.25 mm |
| S2 Surface | Ground |
| Cleaning | Non-abrasive method, acetone or isopropyl alcohol on lens tissue recommended |
