Summary for optical finish on paraboloid surface Discussion
Optical finish on a deep paraboloid surface is the core problem: Andrey Revyakin asked for an affordable way to make deep concave paraboloid mirrors in low-expansion materials such as borosilicate glass, invar, macor, or covar, with surface roughness under 100 nm and a budget under $1,000 per part. He described a 150 mm-diameter paraboloid about 143 mm deep and said diamond turning was too expensive while epoxy spin-casting gave surface quality far worse than needed. The excerpt provided does not include any replies, so no solution or alternative process is given in the visible thread text.
Q. Hi all, I run a research lab in molecular imaging, we are looking for an affordable method (<$1,000 per piece) to make deep paraboloid concave mirror surfaces, in materials with low thermal expansion (borosilicate glass, invar, macor, covar) suitable for optical imaging (surface roughness <100 nm). An example of a our parabolic surface of interest: f=x^2/40, where x is the distance from the centre; a 150 mm-diameter paraboloid described by this formula has an f=10 mm, and is about 143 mm deep. So far we have looked at diamond turning (too expensive) and epoxy spin-casting (surface quality 100x worse our spec).
Andrey Revyakin
principal investigator – Leicester, UK
October 26, 2015