Research on New Stitching Interferometric Testing for Cpp

The test of wavefront of large aperture continuous phase plate(CPP) is difficult to obtain by whole aperture once because of CPP's characteristic such as large phase depth and large phase gradient, so sub-aperture stitching technique is often used to test the CPP's wavefront in whole aperture. We analysed some problems in the traditional sub-aperture stitching test and put forward a new stitching model mathematically in order to improve the precision in CPP's sub-aperture stitching test. We have found that this new model is available by a serial experiments.