Optimized reflective wide-angle Michelson phase-stepping interferometer

A fully achromatic wide-angle interferometer that uses cat's-eye retrorefle ctors has been developed for optical Doppler imaging in the ultraviolet reg ion. Here the solar flux is much weaker than in the visible, so the solar b ackground control system ordinarily used in spacecraft optical instruments becomes unnecessary, which results in a much smaller instrument and a broad er viewing geometry. The theory and the test results associated with the de velopment of this instrument are described. Minimizing the aberrations invo lved in cat's-eye geometry resulted in optimum cat's-eye and interferometer designs. The results of tests conducted in the visible and the near-UV reg ions demonstrated experimentally that the field of view of the interferomet er is 5 degrees and that the residual wave distortions are approximately 1/ 8 wave with visibilities sufficient for high-resolution Doppler imaging. (C ) 2000 Optical Society of America OCIS codes: 120.3180, 080.1010.