Magnesium fluoride (MgF₂)

      Materical
      Diameter Tolerance
      Thickness Tolerance(h)
      Surface Quality
      Parallelism
      Clear Aperture
      Wavefront Distortion
      Protective Bevel

Magnesium Fluoride single crystal
+0.0/-0.1mm
+/-0.2mm
40-20 scratch and dig
1 arc minutes
>80%
λ/2 per 25mm @632.8nm