Laboratory Testing of a Phased Induced Amplitude Apodization (PIAA) Coronagraph

We present high-contrast images from laboratory testing of a Phase Induced Amplitude Apodization (PIAA) coronagraph at NASA's High Contrast Imaging Testbed (HCIT). Using a deformable mirror and wavefront estimation and control algorithms, we create a "dark hole" in the monochromatic point-spread function with an inner working angle of 2.05 fλ/D, with a mean intensity 3.5×10 -8 . We discuss the contributions to this floor, and the techniques being developed to improve it. We also present simulations that investigate the effect of Lyot stops of various sizes, and conclude that a Lyot stop is necessary for 10 -9 performance but that an annular postapodizer is not necessary.