Simultaneous phase-shift point diffraction interferometer and method for detecting wave aberration

A simultaneous phase-shift point diffraction interferometer, comprising:

• an ideal spherical wave generation module (5),
• an image plane mask (8),
• a polarization phase shift module (10),
• a two-dimensional polarization imaging photodetector (11), and
• a data processing unit (12) connected with the two-dimensional polarization imaging photodetector (11),
• wherein the ideal spherical wave generation module (5) is located in the object field of the optical system to be measured (7) and used for generating two beams, a left-handed circularly polarized light and a right-handed circularly polarized light;
• the image plane mask (8) is located on the image plane of the optical system to be measured (7), and comprises a light-transmitting window and a filtering circular hole, the light-transmitting window is used for allowing an spherical wavefront generated by the spherical wavefront generation module (5) to pass through to form measurement light with imaging system wave aberration information via the imaging system to be measured (7), and the filtering circular hole is used for generating reference spherical wave;
• and the polarization phase shift module (10) is used for converting input light into output light with different polarization states, and after realizing polarization phase shift, the two-dimensional polarization imaging photodetector (11) collects and stores measurement data.