The high-contrast coronagraph for direct imaging earth-like exoplanet at the visible needs a contrast of 10^(-10) at a small angular separation of 4 lambda/D or less. Here we report our recent laboratory experiment that is close to the limits. The test of the high-contrast imaging coronagraph is based on our step-transmission apodized filter. To achieve the goal, we use a liquid crystal array (LCA) as a phase corrector to create a dark hole based on our dedicated focal dark algorithm. We have suppressed the diffracted and speckle noise near the star point image to a level of 1.68 x 10^(-9) at 4 lambda/D, which can be immediately used for the direct imaging of Jupiter like exoplanets. This demonstrates that high-contrast coronagraph telescope in space has the potentiality to detect and characterize earth-like planets.
@article{arxiv.1406.2364,
title = {A high-contrast coronagraph for earth-like exoplanet direct imaging: design and test},
author = {C. C. Liu and D. Q. Ren and J. P. Dou and Y. T. Zhu and X. Zhang and G. Zhao and Zh. Wu and R. Chen},
journal= {arXiv preprint arXiv:1406.2364},
year = {2014}
}