Dispersion-compensated polarization Sagnac interferometer with high imaging quality

Abstract Multistage diffraction of a dispersion-compensated polarization Sagnac interferometer (DCPSI) reduces the fringe visibility of interference fringes generated in a focal plane array, thereby leading to the poor quality of the reconstructed polarization images. In this paper, a double total reflection prism between the DCPSI and imaging lens is added to limit the effect of multistage diffraction and improve the imaging quality. First, the influence of multistage diffraction on the interference fringes and the ratio of fringe amplitude to the background was analyzed. Second, the range of angles of the two right angle prisms was calculated. Simulation and experiment were carried out to prove the superiority of the proposed method. Result shows that the ratio of fringe amplitude to the background increases from 1/5 to 1/3 and from 1/10 to 1/6 in simulation and experiment when a double total reflection prism structure is added respectively. This method can reduce the influence of multistage diffraction on interference fringes and improve the image quality of DCPSI effectively.