Title: Design and experimental test of an optical vortex coronagraph,
Abstract: The optical vortex coronagraph (OVC) is one of the promising ways for direct
imaging exoplanets because of its small inner working angle and high
throughput. This paper presents the design and laboratory demonstration
performance at 633nm and 1520nm of the OVC based on liquid crystal polymers
(LCP). Two LCPs has been manufactured in partnership with a commercial vendor.
The OVC can deliver a good performance in laboratory test and achieve the
contrast of the order 10^-6 at angular distance 3{\lambda}/D, which is able to
image the giant exoplanets at a young stage in combination with extreme
adaptive optics.