A catadioptric imaging system for an interferometer includes a beamsplitter plate for reflecting a beam of light to a concave mirror for transmitting reflected light from the mirror. The beamsplitter reflections and transmissions produce opposite sign spherical aberrations. A refractive
A catadioptric imaging system is used to form a converging test beam for measuring large aperture optical elements having convex spherical surfaces. A beamsplitter block divides a collimated beam of coherent monochromatic light from a laser source into a test beam and a reference bea
