Alignment error analysis of the snapshot imaging polarimeter

A snapshot imaging polarimeter (SIP) system is able to reconstruct two-dimensional spatial polarization information through a single interferogram. In this system, the alignment errors of the half-wave plate (HWP) and the analyzer have a predominant impact on the accuracies of reconstructed complete Stokes parameters. A theoretical model for analyzing the alignment errors in the SIP system is presented in this paper. Based on this model, the accuracy of the reconstructed Stokes parameters has been evaluated by using different incident states of polarization. An optimum thickness of the Savart plate for alleviating the perturbation introduced by the alignment error of the HWP is found by using the condition number of the system measurement matrix as an objective function in a minimization procedure. The result shows that when the thickness of a Savart plate is 23 mm, corresponding to the condition number 2.06, the precision of the SIP system can reach to 0.21% at 1° alignment tolerance of the HWP.