Current developments on optical asphere and freeform metrology

Abstract

Two techniques for the measurement of aspheres as well as freeforms are presented. The first method, the tilted wave interferometer, is a full aperture interferometric measurement method without any moving parts during the measurement. The second method applies an optical single point sensor in conjunction with two translational and one rotational axes. Both techniques are compared by measuring a selected asphere and a special freeform surface. Differences between both measurement principles are discussed.