KECK 好像這
https://www.pinterest.com/pin/567383253040374382/The vortex mask shown at left is made out of synthetic diamond, 1 centimeter in diameter an0.3 millimeters thick. The image at right zooms into the mask's center, highlighting its concentric grooves, which have a thickness about a hundred times smaller than a human hair. This vortex coronagraph was recently installed inside NIRC2 (Near Infrared Camera 2), the infrared imaging camera at Keck. It can image planetary systems and brown dwarfs closer to their host stars than any other instrument.