[ATM] Aplanatic Beamsplitter Foucault

[aneves]

Hi All,

I've always wanted to have on axis foucault tester that could be used in an autocollimation setup without inducing astigmatism on short focus optics. The idea of using a cube beamsplitter in the setup was always brushed off, since a thick plate would induce spherical aberation into the setup. I decided to build a aplanatic cube beamsplitter where the front face of the cube is ground to the shape of a convex lens and the other surfaces to a concave shape. With oslo I came to a setup that indicated that this aplanatic beam splitter would not induce spherical aberation. I have started grinding the cube, but since I am no expert in Optical design, I've been wondering  I am overlooking something! Can anyone shed some light as if this setup will really work.

Regards,

Alfredo