Coating Uniformity Correction
For large and steeply curved lenses, an optical coating will be thinner at the edge of the optic unless corrected. For transmitting optics, this non-uniformity can lead to significantly reduced transmission towards the edge of the clear aperture. Optimax has developed a deterministic approach to correct coating uniformity on even the most steeply curved lenses; ensuring good spectral performance and high transmission across the entire clear aperture.
In the optic pictured here, a coated 200mm diameter, 150mm convex radius of curvature lens. The left side of the lens shows the variable reflection from uncorrected coating non-uniformity (multilayer is 15% thinner at edge than center). The right side shows a uniformity corrected surface; reflectivity is the same from center to edge.
Design, specification, and procurement of optical coatings all benefit when the designer has a good understanding of measurement techniques and uncertainties.