Abstract

A new algorithm is developed to test spherical aberration of aspheric surfaces without a null lens. It is based on the fact that spherical aberration can be balanced by defocus. Therefore, if the amount of defocus and locations of the balanced zone are found, the surface profile of an aspheric surface can be found zone by zone as the amount of defocus is adjusted. Simple methods are suggested to find locations of phase minimum for determining locations of the balanced zone and the position of paraxial focus.

© 1991 Optical Society of America