Design and experimental test of an optical vortex coronagraph

Using an optical vortex coronagraph (OVC) is one of the most promising techniques for directly imaging exoplanets because of its small inner working angle and high throughput. This paper presents the design and laboratory demonstration performance of an OVC based on liquid crystal polymers (LCPs) at 633 nm and 1520 nm. The OVC can deliver good performance in laboratory tests and achieve a contrast of 10^-6 at an angular distance of 3λ/D, which can be implemented for imaging young giant exoplanets in combination with extreme adaptive optics.