Paraboloidal mirror surfaces transform plane wavefronts into spherical ones and vice versa. This allows us to perform an interferometric measurement of its shape without the need of compensating optics or a CGH. From measurement's point of view there are good preconditions to manufacture high accuracy paraboloidal surfaces. On the other hand machining has to deal with the aspherical deviation to the best-fitting sphere. Depending on the amount of this deviation and the material of the mirror, different machining technologies are applied to bring the surface into paraboloidal shape. Off-axis paraboloids provide even more challenges in machining. There are two accepted approaches for manufacturing off-axis precision paraboloids. One way is to figure and polish a rotationally symmetric part with subsequent separating the off-axis elements from the parent paraboloid. On the other hand you can machine the single parts right from the start. In this case the surface is a kind of freeform. In this paper we discuss the manufacturing of on-axis and off-axis paraboloidal mirrors applying various methods.

Date Published: 14 May 2007
PDF: 4 pages
Proc. SPIE 10316, Optifab 2007: Technical Digest, 103161D (14 May 2007); doi: 10.1117/12.718630

Published in SPIE Proceedings Vol. 10316:
Optifab 2007: Technical Digest
James J. Kumler; Matthias Pfaff, Editor(s)