Due to the special properties of asphere lens, the testing of it is more difficult than that of spherical lens. In this paper, the development of a new method using the liquid crystal spatial light modulator (SLM) to measure the accuracy of an aspheric surface is presented. The surface form was measured using a new component as the compensator lens in conjunction to provide an interferogram representing the aspheric form deviation from the nominal. Interferograms are decoded using a spatial-carrier phase shifting technique. The interferometric data is compared to data obtained using a contact stylus profilometer. The system can be mounted over a polishing machine and used for on-line testing of aspheric mirror surfaces.
