Vector vortex coronagraph experiments in vacuum towards 10-10 contrast

Starlight suppression to levels of contrast of 1×10−10 with an internal coronagraph would allow for detection and spectral characterization of Earth-analogs. Many coronagraph architectures have been proposed to address this science case. Among them, the vector vortex coronagraph (VVC) stands out for its exquisite sensitivity especially at small angular separations. However, the VVC has yet to demonstrate 1×10−10 contrast in the laboratory. The limitation of VVCs with respect to the Lyot Coronagraph, which holds the contrast record, has been thought to be the vortex mask. Indeed, the mask fabrication imperfections limit how well the deformable mirrors can suppress starlight in the image during wavefront control. Furthermore, the polarization leakage inherent to the VVC has not been fully addressed as a source of incoherent light that limits this type of coronagraph's performance. Our new experiments in the Decadal Survey Testbed confirm these suspicions. Here we present the results of these experiments with a comprehensive characterization of our two best VVC masks.