Surface testing methods of aspheric optical elements

In this paper,several aspheric testing methods for different fabrication steps and their new research progresses are introduced. Especially,we emphasis on the testing methods for precision polishing step,in which subaperture stitching interferometric testing and non-null partial compensating testing method are described in detail. Moreover,several combined interferometric testing methods which perform well in measuring large and steep aspherics are introduced. In addition,we provide a general description of free-form surface testing. The further development of aspheric surface testing methods is also prospected.