The demands on optical metrology such as Fizeau interferometers increase steadily. Typically, a Fizeau lens design consists exclusively of several spheres. Since there is a growing need for larger measuring ranges as well as higher NA of Fizeau lenses, classical spherical Fizeau lenses increasingly reaching their limits. In this paper, a prototype of an innovative transmission sphere comprising aspheric surfaces is introduced and some results and new findings of the manufacturing and testing are presented.
"Enhanced measuring range with aspheric transmission spheres", Proc. SPIE 10448, Optifab 2017, 1044829 (16 October 2017); doi: 10.1117/12.2279776; https://doi.org/10.1117/12.2279776