Errors Correction Analysis of Wavefront Testing in Quadriwave Lateral Shearing Interferometry

The quadriwave lateral shearing interferometry (QWLSI) based on double birefringent crystals of beam displacer (DBCs-BD), which can generate the lateral shearing interference wavefront of four beams of overlapped replicas in the DBCs-BD orthogonal directions. When the replica waves of overlapped incident to the analyzer, and it’s the direction of transmission axis is set as 45° or 135°, the QWLSI’s polarization interferogram can be obtained. This paper deduced the principle of QWLSI in detail, and showed the phase retrieval by the Fourier analysis of the QWLSI’s interferogram, then the wavefront can be reconstructed by using the differential Zernike polynomial fitting. In our investigation, the correction range of PBD’s orthogonal angle error is within –0.5° ~ 0.5°, the maximum error in PV: 0.0012λ and the maximum error in RMS: 1.3789×10-4λ in wavefront reconstruction. Moreover, when the testing light tilts to incident on the PBD in the range of –0.4° ~ 0.4°, by correcting the shear distance be used for wavefront reconstruction to achieve high-precision wavefront testing result. Finally, the experiment shows that the DBCs-BD-QWLSI exhibits feasibility, and high precision.