Fig. 1. Dynamic point diffraction interferometer based on PMA

Fig. 2. Schematic diagram of optical path matching

Fig. 3. Schematic diagram of the experiment

Fig. 4. Interferogram collected by experiment. (a) Single image; (b) four phase-shifting interferograms

Fig. 5. Measurement results of surface shape. (a) Point diffraction interferometer; (b) ZYGO spherical interferometer

Fig. 6. PV and RMS measured by 12 repeated experiments

Fig. 7. Vibration spectrum diagrams of the platform and the corresponding phase-shifting interferograms. (a) Without external vibration; (b) with external vibration

Fig. 8. RMS obtained by averaging different numbers of phase images

Fig. 9. Translation alignment error between focusing beam and pinhole

Fig. 10. Change curve of light intensity transmittance versus offset. (a) Offset in one direction; (b) offset in two directions

Fig. 11. Relationship between the contrast of the interferogram of the mirror under test and the light intensity ratio