A demonstration test of the dual-beam polarimetry differential imaging system for the high-contrast observation

We propose a dual-beam polarimetry differential imaging test system that can be used for the direct imaging of the exoplanets. The system is composed of a liquid crystal variable retarder (LCVR) in the pupil to switch between two orthogonal polarized states, and a Wollaston prism (WP) that will be inserted before the final focal focus of the system to create two polarized images for the differential subtraction. Such a system can work separately or be integrated in the coronagraph system to enhance the high-contrast imaging. To demonstrate the feasibility of the proposed system, here we show the initial test result both with and without integrating our developed coronagraph. A unique feature for this system is that each channel can subtract with itself by using the retarder to rotate the planet's polarization orientation, which has the best performance according to our lab test results. Finally, it is shown that the polarimetry differential imaging system is a promising technique and can be used for the direct imaging observation of reflected lights from the exoplanets.