Interferometer as an Imaging System

The primary function of an interferometer is to produce a set of rays normal to the ideal test surface. This is often aided by the presence of a null lens for aspheric mirrors. However, there is an important secondary function...imaging. In commercial systems there is always a control for imaging the test optic’s aperture. In laboratory practice what’s usually done is to simply obtain a sharp image of the mirror rim/edge.  But we should ask ourselves how well an interferometer performs this imaging function. Are the design criteria  between the two functions really compatible? In this presentation we provide an initial look into this question. We will do so in the context of the Fizeau interferometer since this type is currently the main industry workhorse. The test optic employed will be a parabolic mirror and also an off-axis component of that mirror, i.e. an OAP. A null lens will connect the aspheres to the Fizeau. Our chief  investigative tool will be optical modeling. The code employed is Zemax.

Joe Geary

UAHuntsville