The invention relates to an aspheric
surface shape detection
system and method based on polarized light
wavefront modulation. The
system comprises a
laser interferometer, a first aperture diaphragm, a polarization splitting
prism, a 1 / 4 wave plate and a to-be-detected aspheric surface which are coaxially arranged, and a
half wave plate, a second aperture diaphragm and a
spatial light modulator which are coaxially arranged, before the
laser interferometer emits spherical
waves, the polarization state is changed into a horizontal line polarization state after passing through the first aperture diaphragm and the polarization splitting
prism, the polarization state is changed into a
circular polarization state after passing through the 1 / 4 wave plate, the spherical
waves are reflected on the aspheric surface to be measured, the reflected light is changed into a vertical line polarization state after passing through the 1 / 4 wave plate, and the reflected light is reflected on a polarization splitting film of the polarization splitting
prism. And the light passes through the second aperture diaphragm and is modulated by the
spatial light modulator, the modulated light returns along the original light path to form interference fringes, and the interference fringes are analyzed by the
laser interferometer to obtain measurement data. Compared with the prior art, the method has the advantages of no need of additional compensation elements, easiness in adjustment and measurement, high universality and the like.