Interferometric testing of annular apertures

摘要

Abstract: Zernike circle polynomials generally employed in interferometric mastermind fitting software fail on an annular dominion. Therefore, when testing catadioptric optics erroneous results may be obtained. We performed interferometric measurements on annular pupils at increasing obscuration ratios, and we fitted the resulting aberration wave-fronts using either Zernike circle polynomials and another polynomial set orthogonal over an annulus. The results obtained with the two different sets are compared and the limits of the standard interferometric fitting software are pointed out. !6