Fig. 1. Optical path of off-axis aspheric surface interferometric testing by CGH

Fig. 2. Design residuals of main area

Fig. 3. Model of linear grating

Fig. 4. Relationship between reflectivity of alignment holographic and fringe contrast

Fig. 5. Relationship between etching depth and reflectivity when fringe contrast maintains 1

Fig. 6. Fabrication process of hybrid type CGH

Fig. 7. Physical of hybrid type CGH

Fig. 8. Optical path of CGH testing

Fig. 9. Refracive fringe in CGH alignment area

Fig. 10. (a) Fringe in main area (b) Detection results of main area